January 12

2021
BASIC CONCEPTS OF
AGRICULTURAL ENGINEERING

MCQS BANK FOR POSTS OF ASSISTANT AGRICULTURAL ENGINEER/WATER MANAGEMENT

ENGR. MUHAMMAD
OFFICER/ IRRIGATION ENGINEER/ ASSISTANT DIRECTOR 2021 Edition (PPSC, FPSC, NTS,
OTS, PTS CTS). IT IS COMPILED THROUGH VARIOUS SOURCES. ANEES. KAMRAN
MCQS BANK FOR POSTS OF ASSISTANT AGRICULTURAL ENGINEER/WATER MANAGEMENT OFFICER/
LANDSCAPE ENGINEER/ ASSISTANT DIRECTOR 2021 Edition (PPSC, FPSC, NTS, OTS, PTS CTS).
(COMPILED THROUGH VARIOUS SOURCES BY ENGR.ANEES.KAMRAN/PMAS ARID AGRICULTURE of
UNIVERSITY RAWALPINDI)

1- A man can develop 0.1 hp.

2- The thermal efficiency of diesel engine varies between 32 and 38 percent.
3- The thermal efficiency of petrol engine varies between 25 and 32 percent.
4- The extra high speed engines used in knapsack sprayers are powered by
petrol.
5- The velocity required to operate wind mill is more than 10 km/h.
6- Bench terracing is also called as Staircase forming.
7- Two wind mills equivalent to 1.0 hp.
8- The land holding of small former(less than 4 ha), marginal former (4 to 10 ha),
large former (more 10 ha).
9- Grassed waterways are used as Outlets.
10- The primary objective of level bench terrace is to conserve water and control
erosion.
11- The low speed engine(less than 350 rpm), medium speed (between 350 to
1000 rpm), high speed (more than 1000 rpm).
12- The single cylinder engine is generally used in stationary engine.
13- The stream engine is single stroke engine.
14- The two stroke engine is petrol engine.
15- The four stroke engine is diesel engine.
16- The carburetor is main part of petrol engine.
17- Diesel engine works on principle of Diesel cycle.
18- The injector and fuel pump are the heart of diesel engine.
19- In two stroke cycle engine, one power stroke is obtained after every one
revolution of crankshaft.
20- In four stroke cycle engine, one power stroke is obtained after every two
revolution of crankshaft.
21- The carburetor of an engine is used to mix fuel with air.
22- The firing order of 4-stroke 4-cylinder engine is 1342.
23- The firing order of 4 stroke 6-cylinder engine is 153624.
24- The firing interval of 2-stroke 2-cylinder engine is 360.

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LANDSCAPE ENGINEER/ ASSISTANT DIRECTOR 2021 Edition (PPSC, FPSC, NTS, OTS, PTS CTS).
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MCQS BANK FOR POSTS OF ASSISTANT AGRICULTURAL ENGINEER/WATER MANAGEMENT OFFICER/
LANDSCAPE ENGINEER/ ASSISTANT DIRECTOR 2021 Edition (PPSC, FPSC, NTS, OTS, PTS CTS).
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25- The firing interval of 4-stroke 4-cylinder engine is 180.
26- The 1st IC engine was invented in 1876.
27- The compression ratio of diesel engine is 14 to 22:1.
28- The compression ratio of petrol engine is 4 to 8:1.
29- The air fuel ratio of diesel engine is 8:1.
30- The air fuel ratio of petrol engine is 16:1.
31- The IHP of the engine indicates Power on piston.
32- The BHP of an engine indicates Power on flywheel.
33- The gasket sealing is the most difficult problem at head.
34- The camshaft in an engine is always mounted parallel to crankshaft.
35- The piston skirt clearance at room temperature is 0.04.
36- The piston pin of some engine is offset to left side.
37- The primary purpose of ring expander is to make up for cylinder, wear.
38- The connecting rod of an engine connects the crankshaft with piston.
39- The oil pan of an engine is made of steel or aluminum.
40- The counter weight on a crankshaft is located opposite to big end bearing.
41- The camshaft controls valves (opening, closing, and timing).
42- The pushrod is located between tappet and rocker arm.
43- A six cylinder engine with possible number of firing orders is 4.
44- Valve timing diagram is a function of engine speed.
45- The specific fuel consumption of diesel engine is 200gm/bph/hr.
46- The specific fuel consumption of petrol engine is 290 gm/bph/hr.
47- When the stroke: bore ratio of an engine increases, the volumetric efficiency
of the engine decrease.
48- The piston speed of an engine is equal to 2 LN.
49- Oil pump is driven by timing gear.
50- The compression pressure of diesel engine varies from 35-50 kg/sq. cm.
51- Flywheel is made of cast iron.
52- The stroke bore ratio of tractor engines varies from 1 to 1.25.
53- The inlet valve of four-stroke engine opens at 5” before TDC.
54- Working temperature of diesel engine ranges from 71 to 82 C.
55- Working temperature of petrol engine ranges from 82 to 88 C.
56- White smoke indicates presence of water in fuel.
57- Blue smoke indicates burning of lubricants in cylinder.
58- The specific fuel consumption of diesel engine is less than petrol engine.

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59- IHP (100%) > BHP (80-90%) > FHP (10-20%).

60- The clearance volume is the volume of air or mixture left in the cylinder when
piston is at TDC.
61- The compression pressure in petrol engine (6-10 kg/sq.cm), and in diesel
engine (35-50).
62- The firing interval of 2-stroke engine is determined by 360/no.of cylinder.
63- The efficiency of external combustion engine ranges from 10-15 %.
64- The weight of diesel engine per hp is heavier than petrol engine.
65- Piston of an engine is made of cast iron or aluminum alloy or nickel iron alloy.
66- Gudgeon pin of engine piston is made of cast hardened steel.
67- Piston pin connected piston with connecting rod.
68- IC engine was invented by Nicolas Otto.
69- The work of crank shaft is to turn the flywheel.
70- The common face and seat angle of valve is 45.
71- The four stroke engine are low, high, medium speed.
72- The two stroke engine are only high speed engine.
73- F-head type valves are used in engines has pre-combustion chamber.
74- I-head type valves are generally used in tractor engines and stationary
engines.
75- In T-head type engine, the valves are on one side.
76- The cam lobes of camshaft helps in opening and closing the valves.
77- The teeth on the crankshaft gear is half to the camshaft gear.
78- When cam gear rotates one time the crankshaft gear will rotate two times.
79- Firing order of an engine indicates sequence of power stroke.
80- The volume displaced by one stroke of piston is swept volume.
81- The pre-combustion chamber is found in diesel engine.
82- Distance travelled by piston from TDC to BDC is stroke.
83- Ratio of BPH to IHP is mechanical efficiency.
84- The gear used in timing gear is spur gear.
85- Gaskets are made of copper and asbestos.
86- The gaskets are used to prevent leakage.

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UNIVERSITY RAWALPINDI)

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UNIVERSITY RAWALPINDI)

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MCQS BANK FOR POSTS OF ASSISTANT AGRICULTURAL ENGINEER/WATER MANAGEMENT OFFICER/
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UNIVERSITY RAWALPINDI)

87- The temperature at which fuel catches fire is flash point.

88- The lowest point at which fuel begine to crystallize is cloud point.
89- The temperature at which fuel begins to vaporize is smoke point.
90- The specific gravity of petrol (0.73), powering (0.82), high speed diesel
(0.88).
91- The total number of rings on piston may vary from 3-7.
92- The firing order of 8-cylinder engine is 15426378.
93- The flywheel is mounted on rear end of crankshaft.
94- Constant speed engine is used in electric generator.
95- Constant speed governor is used in stationary engine.
96- If stroke: bore ratio of an engine increase, the thermal efficiency increase.
97- Black smoke indicates engine is overloaded.
98- The violent noise head in engine during process of combustion is
detonation.
99- The process of removal of burnt gases from the engine cylinder is
scavenging.
100- The IHP of an engine was measured by Indicator.
101- The best hydrocarbons from detonation point of view are Aromatics.
102- The calorific value of gasoline is 45 MJ/kg.
103- The purpose of governor in the engine to regulate the engine speed.
104- The calorific value of petrol (8150 Kcal/liter), diesel (9400 Kcal/liter).
105- The anti-knock quality of petrol fuel is determined by Octane number.
106- The anti-knock quality of diesel fuel is determined by Cetane Number.
107- The viscosity of oil denoted by a number is SAE number.
108- Bomb calorimeter is used for determining Calorific value of fuel.
109- Junker’s calorimeter is used for determining the calorific value of Gaseous
fuels.
110- The boiling range of petrol is 300 to 200C.
111- General formulas of Paraffin (CnG2n+2), Naphthenes (CnH2n), Aromatics
(CnH2n-6)

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112- The boiling range of Kerosene is 200 to 300C.
113- The API gravity of light diesel (22), high speed diesel (32), petrol (61), water
(10).
114- The quality of fuel is judged by Volatility.
115- Molecular formula of diesel is C11H16.
116- The specific gravity of fuel is measured by Hydrometer.
117- Detonation refers to the Engine knocking.
118- The detonation takes place during combustion.
119- Distillation test measures the Calorific value.
120- Cetane rating of commercial diesel fuel is 30-60.
121- The specific heat of petrol (2.1 KJ/kgC), diesel (1.9).
122- The work of choke is supply of rich mixture.
123- The fuel injection pump is used to supply fuel to multi cylinder in engine.
124- Air injection pumps are mostly used in heavy duty stationary engine.
125- The pipe line used to supply the fuel to injector is high pressure line.
126- The first butterfly valve of carburets or controls the flow of air fuel mixture.
127- The second butterfly valve of carburetor is Choke.
128- Choke controls the amount of air.
129- Venturi tube is provided in carburetor for producing low pressure.
130- A device for regulating the fuel supply in main jet of carburetor is
Economizer.
131- Chemically correct air mixture ratio for Otto cycle engine is (15:1), leanest
mixture (20:1), richest mixture (8:1).
132- The primary fuel filter is made of cloth and secondary (paper).
133- The primary fuel filter is used to remove particles of size 5 Macron and
secondary (2 Macron).
134- Animal fat lubricants are gummy and waxy type.
135- Mineral lubricants are most popular for engines and machines.

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Power Transmission in Tractor:

136- The power transmission system consists of: (a) Clutch (b) Transmission gears
(c) Differential (d) Final drive (e) Rear axle (f) Rear wheels. Combination of all
these components is responsible for transmission of power.

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A) Clutch:
137- When two revolving friction surfaces are brought into contact and pressed,
then they are united and start to revolve at the same speed due to the friction
force between them. This is the basic principle of a clutch.

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B) Power Transmission Gears:

138- Initially, power and torque from the engine comes into the front of the
transmission and rotates the main drive gear (or input shaft), which meshes
with the cluster or counter shaft gear -- a series of gears forged into one piece
that resembles a cluster of gears.

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C) Differential:
139- Differential unit is a special arrangement of gears to permit one of the rear
wheels of the tractor to rotate slower or faster than the other. While turning
the tractor on a curved path, the inner wheel has to travel lesser the tractor to
move faster than the other at the turning point.

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D) Final Drive:
140- Final drive is a gear reduction unit in the power trains between the differential and
the drive wheels. Final drive transmits the power finally to the rear axle and the wheels.
The tractor rear wheels are not directly attached to the half shafts but the drive is taken
through a pair of spur gears.

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E) Rear Axle:
141- REAR AXLE CASING The rear axle is one of the components of
the tractor which is present in the differential. Its main function is to transmit
power from differential to wheel. This component is mounted on the back
wheels of the tractor, so it is named as Rear Axle.

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142- The methods used for testing of lubricating oil are Viscosity test, Flash fire
test and Pour point test.
143- Say bolt viscometer is used for Viscosity test.
144- Gravity test is done by using the Hydrometer.
145- Splash system of lubrication is generally used in a single cylinder and
stationary engine.
146- In force feed lubrication system pump is driven by camshaft.
147- A pump used in force feed lubricating system may be positive displacement
type, gear type, and vane type.
148- Grease is a semi-solid lubricant.
149- Lubrication oils are rated by viscosity.
150- Crankcase breather is used for removing water vapor from crankcase.
151- Oil filter of tractor engine is generally changed after 120 hours of work.
152- The crankcase filter is mostly made of oil wetted screen.
153- American Petroleum Institute adopted the classification of engine oils in
1952.
154- ‘Say bolt universal second’ is related with the viscosity of oil.
155- Viscosity of oil expressed at two temperatures is -18 to 99C.
156- Viscosity measured in Centistokes, Centipoises and Redwood seconds.
157- The variation in viscosity of oil with change in temperature is measured by
viscosity index.
158- The fan of radiator is driven with the help of V-belt.
159- The fan of radiator is driven by camshaft.
160- In water cooled engine the water pump used centrifugal type.
161- In radiator, hot water flows at the top.
162- Thermostat valve is used in water-cooled engines.
163- Thermostat valve begins open at 70-75C.
164- In petrol engines thermostat valve fully opens at 82C and diesel (88-90C).
165- Thermostat valve widely opens at about 80C.
166- The pressure of radiator cap is about 0.3 to 0.4 kg/cm2.
167- The boiling temperature of water in the radiator is raised to about 110C.
168- The energy removed by cooling is about 30%.
169- Heat losses by exhaust gases is about 33%.
170- Heat obtained to IHP of total heat generated is 36%.
171- Heat obtained to BHP of total heat is about 26%.

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172- Heat losses by friction and compression etc. is about 10%.
173- In pressured water cooling, the water pressure is kept between 1.5 to 2 bars.
174- In case of air-cooled engine, the reduction of weight of engine is about 20%.
175- Melting point of cast iron (1100C) and aluminum (660C).
176- In spark ignition engines fuel is ignited by Battery ignition system or Magneto
ignition system.

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Complete list of engine components is given below

Different Engine Components:

1- Crankshaft:
177- A crankshaft is a shaft driven by a crank mechanism, consisting of a series of
cranks and crankpins to which the connecting rods of an engine are attached.
It is a mechanical part able to perform a conversion between reciprocating
motion and rotational motion.

178- Crankshafts are made from forged steel or cast iron.

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2- Cylinder head:
179- In an internal combustion engine, the cylinder head sits above the cylinders
on top of the cylinder block. It closes in the top of the cylinder, forming the
combustion chamber. This joint is sealed by a head gasket. Cylinder
heads are made from either cast iron or cast aluminum.

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3- Flywheel:
180- Flywheel, heavy wheel attached to a rotating shaft so as to smooth out
delivery of power from a motor to a machine. The inertia of the flywheel
opposes and moderates fluctuations in the speed of the engine and stores the
excess energy for intermittent use. Flywheels are typically made of steel.

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4- Cylinder Block:
181- A cylinder block is the structure which contains the cylinder, plus any cylinder
sleeves and coolant passages. In the earliest decades of internal
combustion engine development, cylinders were usually cast individually,
so cylinder blocks were usually produced individually for each cylinder.
Cylinder blocks are normally made of cast iron or aluminum alloy.

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5- Carburetor:
182- A carburetor relies on the vacuum created by the engine to draw air and fuel
into the cylinders. The throttle can open and close, allowing either more or
less air to enter the engine. This air moves through a narrow opening called a
venturi. This creates the vacuum required to keep the engine running. The
die-cast body is generally made of either aluminum or zinc.

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6- Piston:
183- A piston is a component of reciprocating engines, reciprocating pumps, gas
compressors, hydraulic cylinders and pneumatic cylinders, among other
similar mechanisms. It is the moving component that is contained by a
cylinder and is made gas-tight by piston rings. Pistons are made from either a
low carbon steels or aluminum alloys.

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7- Exhaust Valve:
184- An exhaust valve is a valve that releases burned gases from a cylinder.
The exhaust valve closes during the initial part of the induction stroke. The
inlet valve usually opens a little before top dead center and the exhaust
valve remains open a little after top dead center. The inlet valve is generally
made of nickel chromium alloy steel and exhaust valve is made of
silchrome steel.

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8- Timing Belt:
185- The timing belt is a rubber belt that synchronizes the actions of the camshaft
and crankshaft to keep your valves safely moving and your engine running. A
timing belt is made of typically rubber with high-tensile fibers.

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9- Connecting Rod:
186- A connecting rod, also called a con rod, is the part of a piston engine which
connects the piston to the crankshaft. Together with the crank,
the connecting rod converts the reciprocating motion of the piston into the
rotation of the crankshaft. Connecting rods are usually drop forged out of
a steel alloy. Aluminum and titanium are both materials that are also used in
the manufacturing of connecting rods for performance vehicles.

10- Fuel Injector:

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187- Injector, a device for injecting liquid fuel into an internal-combustion engine.
The term is also used to describe an apparatus for injecting feed water into a
boiler. Components of fuel injector 125 made from carburized or maraging

steel.

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11- Oil Pump:

188- The oil pump in an internal combustion engine circulates engine oil under
pressure to the rotating bearings, the sliding pistons and the camshaft of
the engine. This lubricates the bearings, allows the use of higher-capacity fluid
bearings and also assists in cooling the engine.

31
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12- Catalytic Convertor:

189- A catalytic converter is an exhaust emission control device that reduces toxic
gases and pollutants in exhaust gas from an internal combustion engine into
less-toxic pollutants by catalyzing a redox reaction. The catalyst component
of a catalytic converter is usually platinum (Pt), along with palladium (Pd),

and rhodium (Rh).

32
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13- Oil Seal:

190- The two major seals in your engine are the front and rear end oil seals, which
are located at either end of the crankshaft, and connect to the flywheel at
one end and the fan at the other. They are also found on, among other places,
the valves in the combustion chamber of your engine. Some of the most
common materials used for oil seals are nitrile.

33
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14- Turbocharcher:
191- A turbocharger consists of a compressor wheel and exhaust gas turbine
wheel coupled together by a solid shaft and that is used to boost the intake
air pressure of an internal combustion engine. The exhaust gas turbine
extracts energy from the exhaust gas and uses it to drive the compressor and
overcome friction.

34
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15- Intake Manifold:

192- Featuring a series of tubes, the intake manifold ensures that the air coming
into the engine is evenly distributed to all the cylinders. This air is used during
the first stroke of the combustion process. The intake manifold also helps cool
down the cylinders to prevent the engine from overheating. The intake
manifold has historically been manufactured from aluminum or cast iron.

35
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16- Water Pump:

193- The water pump, also known as the coolant pump, is the heart of the engine's cooling
system. It is the water pump's job to regulate the coolant flow rate, and to constantly
circulate coolant throughout the engine and cooling system. ... HOUSING - The housing is
the outer shell that encases the water pump. The pump body is most commonly made
of cast iron.

36
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17- Exhaust Manifold:

194- Basically, the exhaust manifold acts as a funnel and is used to collect all of
the engine's emissions (from however many cylinders your vehicle has). Then
once they are in one place and completely burnt, the manifold sends the
emissions into the rest of the exhaust system. Cast iron is the material of
choice for 60 - 70 percent of today's exhaust manifold market.

37
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18- Fan:
195- In automobiles, a mechanical fan provides engine cooling and prevents
the engine from overheating by blowing or drawing air through a coolant-
filled radiator. The fan may be driven with a belt and pulley off the engine's
crankshaft or an electric motor switched on or off by a thermostatic switch.

38
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19- Radiator:
196- Your engine's radiator is one of the most important parts of your cooling
system. Your engine’s temperature is constantly watched by a special
thermostat. When the engine gets too hot, the thermostat
releases engine coolant, or antifreeze, from your radiator into your engine.

39
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20- Spark Plug:

197- Spark plug, also called Sparking Plug, device that fits into the cylinder head
of an internal-combustion engine and carries two electrodes separated by an
air gap, across which current from a high-tension ignition system discharges,
to form a spark for igniting the air–fuel mixture. A standard spark plug
typically features a nickel-alloy outer material fused to the copper-core
electrodes.

40
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198- In battery ignition system primary circuit includes primary coil.
199- Primary coil has small number of turns of heavy wire.
200- Positive plate of battery is made of Lead or Antimony.
201- Negative plate of battery is made of Spongy Lead.
202- A chemical used in the battery for reaction is Electrolyte or Distilled water.
203- Specific gravity of a fully charged battery is 1.280.
204- Specific gravity of a fully discharged battery is 1.20.
205- Specific gravity measured by an instrument is Hydrometer.
206- A container of battery is made of Rubber.
207- The battery used on tractor consists of three or six cell.
208- The voltage developed by each cell of battery is about 2.2 volts.
209- Battery should be recharged when specific gravity 1.225.
210- At greater temperature the infiltration rate is more.
211- Bench terraces are constructed at slope gradient of 10 to 20%.
212- Curve number method estimates the direct runoff.
213- Rainfall intensity is the ratio of rainfall amount to time.
214- Runoff coefficient is the ratio of runoff to rainfall.
215- Most of diesel starting motors are equipped with an overrunning clutch.
216- Hot plugs are used in Powerine tractors.
217- Cold plugs are used in Petrol engine.
218- Spark plug gap setting should be kept between 0.50 and 0.85 mm.
219- In ignition system, magneto is used for supply of spark.
220- Glow plug is used for to heat the air charge of engine.
221- Primary winding of ignition cell consists of 200-400 turns.
222- A primary winding wire has resistance of three ohms.
223- Secondary winding consists of 15000-20000 turns.
224- M modern spark plug has an economical life of about 10000-16000 Km.
225- The gap of spark plug generally should be 0.6 mm.
226- Contact breaker points is generally made have Tungsten.
227- The material commonly used for insulator of spark plug is Alumina.
228- The life of spark plug used in 2-stroke engine as compared to 4-stroke engine
is twice.
229- Spark plug having white center insulator indicates over advanced ignition.
230- Spark plug with a black center insulator indicates stuck-up choke valve in
carburetor.

41
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231- Cold spark plug has short insulator.
232- Hot plug has long insulator.
233- Charge of battery is measured in terms of specific gravity of electrolyte.
234- In lead acid battery, percentage of sulphuric acid is about 35%.
235- The period between start of injection and ignition is called ignition delay.
236- Ignition delay of high-speed engine should be about 0.001 second.
237- Ignition delay of low-speed engine is 0.02 second.
238- Starting motor is engaged with ring gear of engine with the help of sliding
pinion gear.
239- Alternator of a tractor engine is driven by V-bolt system.
240- Speed of alternator with respect to engine speed is twice.
241- In common rail system fuel is supplied by one pressure line to all injectors.
242- Unit injector is driven by camshaft.
243- In individual pump system, fuel is delivered to injector at high pressure of
10000 to 20000 Kpa.
244- Hole type nozzle is generally used in open type combustion chamber.
245- Pintle type nozzle is commonly used in both pre-combustion chamber and
swirl combustion chamber.
246- Pressure in hole type nozzle varies from 17-34 Mpa.
247- Pressure in pintle type nozzle varies as 7-15 Mpa.
248- Accumulator is used in common rail system.
249- The work of accumulator is to keep constant pressure.
250- The size of hole of single hole nozzle is usually larger than 0.2 mm.
251- In multi hole nozzle, the number of holes varies as 4-18.
252- A governor automatically regulates engine speed.
253- Throttle system controls the amount of air fuel mixture.
254- Pneumatic governor is used on diesel and petrol engine.
255- Centrifugal governor is common in tractor engine and stationary engine.
256- The governor used on tractor engine is called variation speed governor.
257- The governor used on stationary engine is constant speed engine.
258- Hit and miss governing system is used in the gas engines.
259- Throttle type governor is kind of hydraulic governor.
260- Variation in engine speed at full load and no load is called speed drop.
261- Centrifugal governor is directly connected with fuel injection pump.
262- Centrifugal governor is also termed as maximum speed governor.

42
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263- All speed governors are directly connected with accelerator pedal and pump
control rack.
264- The main parts of pneumatic governor is venturi unit and pump control rack.
265- Venturi unit is connected to the engine inlet manifold.
266- Diaphragm unit is fitted on fuel injection pump.
267- Venturi unit and diaphragm are connected by vacuum pipe.
268- Tie rod, steering wheel and drag link are the main parts of steering
mechanism.
269- Warm gear used in steering system
270- Gear pump and vane pump are used in power steering system.
271- The complete path of power from engine to wheel is called power train.
272- Pressure plate is an essential part of clutch.
273- Friction plate is part of clutch.
274- The gear used in constant mesh type system is helical gear.
275- The device that permits one of the rear wheels of tractor to rotate faster
than the other at the turning is called differential lock.
276- Crown wheel is a part of differential system.
277- The main function of crown wheel is to transmit power at right angle and to
reduce the speed of rotation.
278- A splined shaft used for taking off power from engine is PTO.
279- Single disc or single plate type clutch is dry type.
280- Multiple disc clutches are wet and dry type.
281- Multiple disc type clutches are mostly used in crawling tractor.
282- Gears are generally made of alloy steel.
283- Lubricants used in gearbox is SAE 90.
284- Transmission oil should be changed after 750 hours.
285- Generally tractor speed in the top gear varies from 18-24 kmph.
286- Differential lock helps to developing full traction in both drive and wheel.
287- A PTO shaft with diameter 3.6 cm and 6 splined, standard PTO rpm will be
540 +-10 rpm.
288- A pro with 21 splined has speed of 1000rpm.
289- Spline in PTO is used for Joining two shaft in line.
290- In sliding gear transmission system, the gear used is spur gear.
291- The hydraulic transmission system is popular in Combines.
292- Spur and helical gears transmit power between two parallel shafts.

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293- Bevel gears transmit power between two shafts are intersecting axis.
294- Spline shafts are used when the torque transmission is in large amount.
295- Hydraulic pump develops a pressure of about 150kg/cm2.
296- Hydraulic system in tractor is mainly used for operating three point hitch.
297- A gear used in the tractor hydraulic system normally is spur type.
298- An accumulator used in hydraulic system is for storing energy.
299- An accumulator is also served as shock absorber.
300- Control valve, Relief valve and Priority valve are used in hydraulic system.
301- Ratio of mass density of substance at certain temperature to the mass
density of water at same temperature is called specific gravity.
302- Specific gravity of petroleum based hydraulic fluid is 0.8.
303- Mass density increase as pressure increase.
304- Mass density decrease with temperature increase.
305- Amount of heat required to raise the temperature of a unit mass by one
degree is called specific heat.
306- Nudging system is used for raising and lowering implements.
307- Average body surface area of a man will be 2.0m2.
308- Unit of noise is Decibel.
309- The frequency range of human ear 16-20000 Hz.

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Tillage Implements:
A) Primary Tillage Implements:
1- Disc Plough:
310- The disc plough is designed to work in all types of soil for functions such as
soil breaking, soil raising, soil turning and soil mixing. It is used to open the
new fields and to process the stony areas. It can be used easily at rocky and
rooted areas.

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2- MB Plough:
311- It is tractor operated implement and it consists of share point, share,
moldboard, landside, and frog, shank, frame and hitch system. The working
of the plough is controlled by hydraulic system of the tractor. Mold board
plough is a primary tillage implement.

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3- Chisel Plough:
312- The chisel plough is a common tool for deep tillage (prepared land) with
limited soil disruption. Its main function is to loosen and aerate the soils, while
leaving crop residue on top. Unlike many other ploughs, the chisel will not
invert or turn the soil.

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4- Subsoiler Plough:
313- A subsoiler or flat lifter is a tractor-mounted farm implement used for deep
tillage, loosening and breaking up soil at depths below the levels worked by
moldboard ploughs, disc harrows, or rototillers.

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B) Secondary Implements:
1- Rotavator:
314- Rotavator is a tractor-drawn implement which is mainly used for seed
bed preparation within one or two passes and is suitable in removing & mixing
residual of maize, wheat, sugarcane etc., thereby, helps to improve soil health
and save fuel, cost, time & energy as well.

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2- Disc Harrow:
315- A disc harrow is a harrow whose cutting edges are a row of concave
metal discs, which may be scalloped, set at an oblique angle. It is an
agricultural implement that is used to till the soil where crops are to be
planted. It is also used to chop up unwanted weeds or crop remainders.

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316- The upper safe noise level is 85 dB.
317- Vibration is measured by accelerometer.
318- Ratio of output vibration to input vibration is called transmissibility.
319- Eicher is the 1st company, which introduced air-cooled tractor.
320- Traction coefficient is maximum in dry field.
321- The 1st tractor demonstration was held at Nebraska.
322- Pressure due to radiator caps raise the boiling points.
323- Coefficient of traction is defined as ratio of drawbar pull to dynamic loads.
324- Power train indicates complete power transmission path.
325- Clutch works on principle of friction.
326- Pain in eardrum starts at a noise level of 115 DB.
327- Range of pressure angle in spur gear is 14-20.
328- Cold spark plug is used in light duty engine.
329- Valve timing diagram is a function of engine speed.
330- In a tractor center of gravity is located at 1/3 of wheelbase ahead of rear
axle.
331- Dog clutch used in power tiller.
332- Pitman arm is part of steering system.
333- Drag link is component of steering system.
334- Hydraulic brakes works on the Pascal’s Law.
335- In tractor three-point hitch is operated by hydraulic system.
336- Top link of tractor is known as tension link or mast or pressure link.
337- Lower link of tractor reduces side draft.
338- If strokes: bore ratio increases the thermal efficiency increases.
339- Tractor operation in lower gear causes more pull.
340- Muffler is provided on tractor to control noise.
341- Supercharger of an engine is driven by crankshaft.
342- Turbocharger of an engine is driven by exhaust gases.
343- One bar is equal to 100Kpa.
344- Bar is the unit of pressure.
345- Fluctuation of engine speed during a cycle depends upon mass of flywheel.
346- Radiator core is made of brass.
347- The grade of oil used during summer season is SAE 40.
348- The grade of oil used in winter season is SAE 30.
349- A function of drawbar in tractors is to hitch the implement.

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Camber Angle:
350- Camber angle is one of the angles made by the wheels of a vehicle;
specifically, it is the angle between the vertical axis of a wheel and the vertical
axis of the vehicle when viewed from the front or rear. It is used in the design
of steering and suspension.

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Caster Angle:
351- The caster angle or castor angle is the angular displacement of the steering
axis from the vertical axis of a steered wheel in a car, motorcycle, bicycle,
other vehicle or a vessel, as seen from the side of the vehicle.

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Toe-in and Toe-out:

352- Negative toe, or toe out, is the front of the wheel pointing away from the
centerline of the vehicle. Positive toe, or toe in, is the front of the wheel
pointing towards the centerline of the vehicle.

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353- Cage wheel used in tractor for improving traction.

354- Depreciation of machine is computed on its fixed cast.
355- Brake mean effective pressure of an engine depends upon its torque.
356- The color of negative plate of lead acid battery is brown.
357- The color of positive plate of lead acid battery is grey.
358- Positive plate of lead acid battery is made of PbO2.
359- Weight transfer is tractor is affected by center of gravity.
360- Dbhp of tractor indicates power on drawbar.
361- Front wheel of tractor is smaller than rear wheel that helps sharp turning.
362- Ply-rating of tyres indicates load-bearing capacity.
363- Toe-in and toe-out are related to front axle of tractor.
364- Angle between center line of kingpin of tractor and vertical line is caster
angle.
365- Negative plate of lead acid battery is made of Pb.
366- In an alternator the magnetic field is produced in the Rotor.
367- The number of winding in the stator of alternator is 3.
368- The ratio of output power to input power for a traction device is called
tractive efficiency.
369- The power required to run the engine at any given speed without production
of useful work is called friction power.
370- Brake horsepower of an engine can be measured by brake dynamometer.
371- Revolution of an engine is measured by tachometer.
372- Drawbar pull is measured by the hydraulic dynamometer.
373- Engine oil should be changed at every 120 hours.
374- Tractor transmission oil should be changed at every 750 hours.
375- Slogging or lugging ability is associated with engine torque.
376- The useful life of tractor is 10,000 hours.
377- A part that connects piston with connection rod is Gudgen pin.
378- Power tiller operates most satisfactorily with rotary tools.
379- In an adiabatic process system heat is constant.
380- Brake works on principle of friction.
381- Soil texture represent the size and proportion of particles making a soil.
382- Brake fluid used in hydraulic brake is mixture of glycerin and alcohol.

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383- When brake is applied the kinetic energy of body is converted into heat
energy.
384- The optimum engine temperature is about 82 deg.
385- Cetane number for commercial diesel fuel varies from 30-60.
386- Loss of value of machine with passage of time is depreciation.
387- The voltage in spark plug at the time of spark is 20,000 V.
388- Heavy smoking in an engine during operation may be due to overload.
389- Relative movement of the wheel in direction of travel for given distance
under load and no load condition is wheel slip.
390- BHP of the engine indicates power on flywheel.
391- Center of gravity of tractor is determined by Suspension method, balancing
method and weighing method.
392- Main constitute of biogas is Methane.
393- The ratio of rolling resistance to dynamic load is coefficient of rolling
resistance.
394- The rear part of a tractor is heavier than the front part of tractor to get higher
tractive efficiency.

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Gears:
1- Spur gears:
395- Spur gears or straight-cut gears are the simplest type of gear. They consist of
a cylinder or disk with teeth projecting radially. Though the teeth are not
straight-sided, the edge of each tooth is straight and aligned parallel to the
axis of rotation.
2- Bevel gears:
396- Bevel gears are gears where the axes of the two shafts intersect and the
tooth-bearing faces of the gears themselves are conically shaped. Bevel
gears are most often mounted on shafts that are 90 degrees apart, but can
be designed to work at other angles as well. The pitch surface of bevel gears is
a cone.
3- Worm gear:
397- A worm gear (or worm drive) is a specific gear composition in which a screw
(worm) meshes with a gear/wheel similar to a spur gear. The set-up allows
the user to determine rotational speed and also allows for higher torque to
be transmitted.
4- Rack and pinion gear:
398- A rack and pinion is a type of linear actuator that comprises a
circular gear (the pinion) engaging a linear gear (the rack), which operate to
translate rotational motion into linear motion. Driving the pinion into rotation
causes the rack to be driven linearly.

58
MCQS BANK FOR POSTS OF ASSISTANT AGRICULTURAL ENGINEER/WATER MANAGEMENT OFFICER/
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UNIVERSITY RAWALPINDI)

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399- An engine is called I head engine when valves are immediately above the
cylinder.
400- A steam engine is an external combustion engine.
401- In hydraulically control hitching system, the equipment vibrates due to lower
oil level or clogging of oil filter or trapping of air in oil filter.
402- Engine in which heat is taken at one constant pressure and reject at another
constant pressure is Otto cycle.
403- When crankshaft of the engine completes one cycle, the camshaft completes
half revolution.
404- The camshaft gear is called halftime gear.
405- The stroke bore of tractor engine is 1.25.
406- The permissible slip for wheel type tyre during slippage testing is 15 to 20%.
407- The permissible slip for crawler tractor during slippage testing is 7 to 10%.
408- The operation to perform to open cultivable land is primary tillage.
409- Finer operation performed for seedbed preparation is secondary tillage.
410- An implement that pulled and guided by single hitch point of a tractor is
trailed implement.
411- An implement that attached to a tractor along hinge and controlled directly
by tractor steering unit is semi mounted implement.
412- An implement that fully supported by the tractor is mounted implement.
413- Jointer and coulter are the parts of MB plough.
414- The part of MB plough that penetrates into the soil and cuts the soil in
horizontal direction is share.
415- The forward end of cutting edge that actually penetrates into the soil and cut
the soil is share point.
416- The front edge of the share which makes horizontal cut in the soil is cutting
edge.
417- The share of MB plough is made Chilled cast iron.
418- The MB plough works on the principle of suction.
419- The stubble type of MB is mostly suitable for grassy land.
420- The slat type of MB is used in sticky soil.
421- The part of MB plough to which all other parts of plough bottom is attached
is frog.
422- In MB plough, a small irregular piece of metal has similar shape to ordinary
plough bottom is gunnel.

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423- A device mould to cut the furrow slice vertically from a land ahead of bottom
is coulter.
424- A part of MB plough which lift, turns and break furrow slice is MB.
425- A wheel used for maintaining uniform depth of ploughing in different soils is
gauge wheel.
426- The part of MB plough that resists the side pressure exerted by the furrow
slice on the MB is landside.
427- The size of MB plough is expressed by width of cut.

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Nut & Bolt:

428- The bolt consists of a head and a cylindrical body with screw threads along a
portion of its length. The nut is the female member of the pair, having internal
threads to match those of the bolt. Washers are often used to prevent
loosening and crushing.

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429- According to Colling, the draft of MB plough on the ground is 18%.
430- According to Colling, the draft of MB plough due to furrow slice is 34%.
431- According to Colling, the draft of MB plough due to cutting slice is 4%.
432- The part of MB plough to which the plough bottom and handle attached is
standard.
433- The maximum clearance under the landside and horizontal surface when the
MB plough is resting on ground surface is vertical suction.
434- In MB plough, the maximum horizontal clearance between the landside and
furrow wall is horizontal suction.
435- The vertical clearance of the MB plough ranges from 3 to 5 mm.
436- Vertical clearance of MB plough influences depth of cut.
437- The horizontal suction of MB plough is 5 mm.
438- The size of light MB plough (100 to 150 mm width of cut), medium (150-200).
439- In standard disc plough, all the discs are fitted on separate standard.
440- In disc plough, the angle at which the plane of cutting edge of disc is inclined
to the direction of travel is called disc angle.
441- In disc plough, the angle at which the plane of cutting edge of disc is inclined
to the vertical line is tilt angle.
442- Disc angle of standard disc plough varies from 4-45 deg.
443- Tilt angle of standard disc plough varies from 15-25 deg.
444- In disc plough, a device used to prevent disc from clogging is scraper.
445- Back furrow and dead furrows are left while ploughing with one-way plough.
446- A MB plough, which is suitable for ploughing along hillside is tow-way plough.
447- In disc harrow, a device used to provide a distance between two discs
mounted on same gang axle is spool.
448- A shaft of disc harrow on which the number of discs is mounted is arbor bolt.
449- The increase in tilt angle of disc plough influences penetration disc.
450- The tilt angle of disc plough influences depth of cut.
451- The disc angle of disc plough influences width of cut.
452- The method of ploughing in which the plough works round a strip of
unploughed land is casting.
453- The method of ploughing in which the plough works round the strip of
ploughed land is gathering.
454- At open trench left between two adjacent strips of land alter the ploughing
is dead furrow.

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455- An undisturbed soil surface of furrow is called furrow wall.
456- A strip of unploughed land that is left at each end of the field for tractor
turning is head land.
457- The top portion of a turned furrow slice is crown.
458- A harrow with two gangs placed end to end is single action disc angle.

Gathering and Casting:

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459- A disc harrow with four gangs in which set of two gangs follow behind the
set of other two gangs is tandem disc harrow.

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460- A raised left at center of the strip of land when ploughing is started from
center to side is back furrow.
461- A harrow, in which is based on a principle that side thrust against the front
gang, is opposed by side thrust of rear gang offset disc harrow.
462- A harrow whose tynes swing back when obstacle encountered is spring tyne
harrow.
463- A special type of harrow with curved knives is acme harrow.
464- The internal angle between the gangs of single action disc harrow is more
than 90 deg.
465- In disc harrow the angle made by the axis of the arbor bolt with the direction
of travel is gang angle.
466- The spacing between discs in light duty harrow is 6-9 inch.
467- The size of disc harrow is determined by maximum width of cut.
468- Acme harrows are mostly used for mulching.
469- The spacing between discs in heavy duty harrow is 10-12 inch.
470- A ridger is used for making channel.
471- Sweeps are used for mulching.
472- A normal ploughing depth is 15 cm.
473- A subsoiler is used to break a hard pan of soil up to a depth of 100 cm.
474- The excessive side draft in disc plough is due to hitching defect.
475- The width and depth of cut of disc harrow is controlled by gang angle
mechanism.
476- The type furrow opener used in zero tillage implement is inverted type.
477- In vertical disc plough, the number of disc varies from 2-32.
478- The shape of furrow cut by MB plough is L-shape.
479- The horizontal component of pull parallel to the direction of travel is draft.
480- The horizontal component of pull perpendicular to the direction of travel is
side draft.
481- Cone penetrometer is used to measure soil compaction.
482- The L-shaped blade of rotary tillers are used for seedbed preparation in hard
and sticky soil.
483- The C-shaped blade of rotary tillers are used for seedbed preparation in
trashy soil.
484- The group of number of discs that is mounted on a gang axle is gang.
485- The forces acting on MB plough are parasitic.

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486- A two-way plough eliminates back furrow and dead furrow.
487- Two-way plough is advantageously working in contour field.
488- Notched coulter work well in heavy trashy field.
489- Share of MB plough is made of C-1095 solid steel.
490- Disc plough works effectively in hard, dry and sticky soil.

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Bearings:
491- Bearings are mechanical assemblies that consist of rolling elements and
usually inner and outer races which are used for rotating or linear shaft
applications, and there are several different types of bearings, including ball
and roller bearings, linear bearings, as well as mounted versions that may use
either rolling.

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492- A coulter attachment is used with MB plough.
493- The spike tooth harrow are used mainly for surface finishing.
494- Puddling is done to achieve non-leaching of water.
495- Dead furrow is made by one-way MB plough.
496- Surface planting with conservation feature of contour listing is ridge planting.
497- Ridge planting is most suitable for high rainfall areas.
498- The disc force into the ground by weight.
499- The disc plough is advantageous over MB plough in respect of suitable for
deep ploughing.
500- Two-way plough implement is suitable for terraced hilly land and it do not
upset of land.
501- Two-way plough does not leave any back as well as dead furrow.
502- Notch coulters are used for cutting heavy trashes.
503- The more draft requirement in MB plough as compared to disc plough for
same depth of ploughing.
504- Standard disc plough is used for deep ploughing.
505- The random scattering of seed on the surface of seedbed is broadcasting.
506- Dibbler is a planter.
507- The dibbling is mostly used for sowing vegetables.
508- The dropping of seeds in furrow lines in continuous flow is drilling.
509- The method of planting in which row-to-row as well as plant-to-plant
distance is uniform check row planting.
510- The most positive seed metering mechanism used in seed drill is fluted roller.
511- Shoe type furrow opener works well in trashy soil.
512- Hoe type furrow opener works well in root infested soil.
513- The procedure of testing seed drill for correct seed rate is calibration.
514- The device used to sow seeds, which are larger in size and cannot be sown
by usual seed drill is planter.
515- The seeding behind plough is done by a device known as malobansa.
516- Small seeds are used in Seed drill for sowing.
517- Planters are used for sowing bolder seeds.
518- 1/10th of area to be sown in nursery required for transplanting paddy
seedling in one hectare of land.
519- Planter is different from seed drill in respect to metering mechanism.
520- A double disc type furrow opener is suitable for trashy soil.

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521- One-way plough requires laying out a field land, starting with Back Furrow.
522- Two-way plough is advantageously working in Contour field.
523- The two-way plough are designed to turn furrow slices to only right.
524- Pain coulter are used in relatively clean field.
525- Notched coulter work well in Heavy trashy field.
526- Share of mould board plough is made of C-1095 sold steel.
527- One-way plough requires laying out a field in lands, ending with Dead furrow.
528- A plough that works effectively in hard, dry and sticky soil is Disc plough.
529- The mould board plough absorb side forces mainly through the Land disc.
530- The bearing used in most of disc harrow is about sealed ball bearing.
531- The maximum operating depth for disc harrow is about One-fourth of disc
diameter.
532- Puddling is done mainly for
533- Land shaping becomes necessary where often the following implement is
used MB plough.
534- Land plane is ideally suited for top finishing.
535- A coulter attachment is used with MB plough.
536- Plough share is made up of Gun metal.
537- The spike of MB plough is expressed in Width of cut.
538- The spike tooth harrows are used mainly for Surface finishing.
539- Puddling is done to achieve Non-leaching of water.
540- Dead furrow is made by One-way MB plough.
541- Surface planting with conservation feature of contour listing is Ridge
planting.
542- The planters are suitable for maintaining distance between
seeds/plants/rows.
543- The most common power transmission system used in seed drill is chain and
sprocket.
544- The metering mechanism used in potato planter is picker wheel type.
545- In cup food metering device, the seed rate is controlled by size of cup.
546- The furrow opener used in black cotton soil is hoe type.
547- The group of number of discs that is mounted on a gang axle is Gang.
548- A two-way plough eliminates Back Furrow and Dead furrow.
549- Ridge planting is most suitable for High rainfall areas.
550- The disc force into the ground by Weight.

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551- The disc plough is advantageous over MB plough in respect of Suitable for
deep ploughing.
552- The implement suitable for terraced hilly land and do not upset the slope of
land is Two-way plough.
553- The plough that does not leave any back as well as dead furrow is Two--way
plough.
554- Mould board plough works on the principle of Suction.
555- The coulters used for cutting heavy trashes are Notch coulter.
556- The tillage practice is desirable in the areas of having hard or compacted
layers below the plough depth is Sub soiling.
557- The versatile implement used for seed bed preparation, ridge-making and
channel shaping is MB plough.
558- The random scattering of seed on the surface of seedbed is broadcasting.
559- Dibbler is a Planter.
560- The dropping of seeds in furrow lines in continuous flow is Drilling.
561- The most positive seed metering mechanism used in seed drill is Fluted
roller.
562- A seed metering mechanism has double faced wheel, one face has a larger
opening for larger seeds and other face has smaller opening for smaller seeds
is internal double run.
563- The furrow opener, which works well in trashy soils, is Shoe type.
564- The part of seed drill that conveys seed or fertilizer from deliver tube to
furrow is Boot.
565- The procedure of testing seed drill for correct seed rate is Calibration.
566- The device used to sow seeds, which are larger in size and cannot be sown
by usual seed drill is Planter.
567- In a seed metering mechanism, only one seed is allowed at a time is Flat drop.
568- The seeding behind plough is done by a device known as Malobansa.
569- The pump is mostly made of Brass.
570- A tank capacity of knapsack sprayer is about 9-22.5 litres.
571- Area that one man can spray in a day is 9.4 ha.
572- Amount of liquid that a man can spray in a day is 90 litres liquid.
573- Hand atomizer is used for spraying in Nursery.
574- The pump is used in power-operated sprayer is Gear type.
575- Swirl plate is a part of Cone nozzle.

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576- Spray gun is known as Lance.
577- The motor of ultra-low volume sprayer is powered by battery of 6-12 volt.
578- Spinning disc is used in Ultra low volume spray.
579- Droplet size of ultra-low volume sprayer varies from 35-100 micron.
580- A machine used to generte and distribute gases or smoke is known as
Fumigator.
581- Flame gun is used for killing the Weeds.
582- Hollow cone nozzle employed on boom type sprayer have spray angle of 60-
95 degree.
583- Nozzle spacing in boom is governed by Axial vertical.
584- Flooding nozzles have spray angle of 100-150 degree.
585- Air blast sprayer is used for Orchards.
586- The pump used in most of the hydraulic sprayers is Positive displacement
pump.
587- Tank of hydraulic pump is made of Metal.
588- The forward operating speed of power sprayer varies from 4.8-8 kmph.
589- The solid cone nozzle is used for Weedicides application.
590- A device used for manual harvesting of crops Sickle.
591- An action involving manual harvesting of crop is Slicing and tearing action.
592- A machine used to cut herbage crops and leave them in swath is Mower.
593- A machine used for cutting of cereal crop Reaper.
594- A machine that cuts the crops and ties them into a knot and uniform sheaves
is called Reaper binder.
595- The material that is left by te harvesting machine in row is Swath.
596- A machine used to cut crops and deliver them in a uniform manner in a row
is Windrower.
597- A mower with rotating helical blades used for cutting is Cylinder mower.
598- Helical blades of mower are arranged in Horizontal cylindrical form.
599- A mower with high speed knife rotating in horizontal plane is known as
Horizontal rotary mower.
600- A mower in which swinging knives are used for cutting is Rail mower.
601- A tractor drawn in semi-mounted mower is operated by Tractor power take
off.
602- Cutter bar of reaper is made of High grade steel.
603- The knife section of a reaper makes a Reciprocating motion.

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604- In proper registered reaper, after each stroke a knife shall stop At the centre
of guard.
605- In power tiller mounted reaper, the rotating power of power tiller in prime
mover is converted into Reciprocating power of cutter bar.
606- The knife moves on the Ledger plate.
607- In reaper, knife clips are placed with Wearing plate.
608- In the reaper, a space between knife clips and wearing plate is about 20-30
cm.
609- The work of shoe in the reaper is to regulate the height of cut.
610- The wearing plate of cutter bar of reaper is made of Mild steel.
611- In reaper, a flat plate with two cutting edges is known as Knife section.
612- In reaper, a knife head of cutter bar is connected to Pitman.
613- Pitman that is used in reaper is a type of Connecting rod.
614- When the knife section of cutter bar stops in the center of its guard after
every stroke is Registration.
615- The vertical conveyer reaper is mostly used for harvesting Cereal crop.
616- In vertical conveyer reaper, the crop to be harvested are guided by Star
wheel.
617- The hand dropper was developed in Japan.
618- The length of cutter bar of tractor front mounted reaper is 1.9-2.1 m.
619- Tractor front mounted reaper is operated at a forward speed of 3.0 km/h.
620- The size of combine is determined by Width of harvest.
621- The cutting width of small size propelled combine ranges from 1.5-2.1 m.
622- Tractor mounted groundnut digger shaker is driven by Tractor PTO.
623- The reel most commonly used in combine now a days is Pick up type.
624- The rack loss should remain between 0.2-0.4 percent.
625- The grain that is carried over the rear of the sieve with chaff and blown out
of the combine is Sieve loss.
626- The optimum value of reel index for minimum cutter bar loss is 1.25 to 1.5.
627- The held typo thresher originated in Japan.
628- The cylinder speed of rotary type thresher is 400 rpm.
629- The drum diameter of rotary type thresher is 43 cm.
630- The size of power thresher is determined by Width of cylinder and straw rack.
631- The threshed gram received at main grain outlets with respect to total grain
input expressed as percentage by mass is Threshing efficiency.

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632- The percentage of grain blown by blower along with bhusa in respect to total
grain input in the thresher by weight is Blower loss.
633- The percentage of healthy grain obtained from all outlets with respect to
healthy grains received from main outlet by weight is Sieve loss.
634- For wheat, the recommended speed of threshing drum is 20-30 m/s.
635- For paddy, the recommended speed of threshing drum is 16-25 m/s.
636- The process of separation of grain from a mixture of grain and chaff is
Winnowing.
637- The power tillage is most suitable for Rotary operation.
638- The minimum soil manipulation is essential for crop production in Minimum
tillage.
639- The seed drill, which is used for direct sowing of seeds in unploughed land
after paddy harvesting is Zero till drill.
640- The shovel of cultivator is made up of Chilled cast iron.
641- The carbon percent in mild steel varies from 0-0.25%.
642- The percentage of carbon in medium carbon varies from 0.25 to 0.5 %.
643- The percentage of carbon III high carbon steel varies from 0.5 to 1.5%.
644- The percentage of carbon in cast iron is 2.5 to 4.5%.
645- The cutting blade used in subsoiler is made from High carbon steel.
646- The term turrel is associated with Sickle.
647- The useful life of self-propelled combine is 6 years.
648- The expected annual use of plough is 2400 hours.
649- The expected annual use of seed-cum-fertilizer drill is 1200 hours.
650- The expected life of tractor mounted combine is 7 years.
651- The expected annual life of harrow is 10 years.
652- The expected life and useful hours of cultivator is 12 years, 3000 hours.
653- The coupling joining two shafts out of alignment is Flexible coupling.
654- A coupling is a device used to connect two shafts together at their ends for
the purpose of transmitting power. The primary purpose of couplings is to
join two pieces of rotating equipment while permitting some degree of
misalignment or end movement or both.
655- The coupling ued for joining two shafts appreciably out of line is Universal
coupling.
656- The coupling used to join to shaft in line is Flanged coupling.

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657- The ratio of reel peripheral speed to forwards speed of combine is termed as
Reel index.
658- Renewable source of energy is Inexhaustible.
659- A reflector used in solar power plant to reflect sunlight is Concave reflector.
660- In solar power plant, the turbine is run by Steam.
661- Solar pond is used to Collect and store the solar energy.
662- The solar cells used in solar panel are used to convert solar energy into
Electrical energy.
663- A type of solar reflector used in solar furnace Concave and spherical.
664- The solar radiation receive by every squre meter 0.64 KJ/sec.
665- In sunlight, the heating rays are Infra-red ray.
666- For working a windmill the minimum speed of wind should be 10 kmph.
667- Wind due to its motion possesses the Kinetic energy.
668- A windmill suitable for water lifting is multiple blade type.
669- The speed of multi-blade rotor is 60-80 rpm.
670- The major constitute of biogas is Methane.
671- The percentage of methane in biogas is 65 per cent.
672- Disgester diameter of biogas plants ranges from 1.1-6 metres.
673- In biogas plants, the depth of digester varies from 3-6 metres.
674- The percentage of carbon dioxide in biogas is about 35-45.
675- Major constituent of biogas is Methane.
676- The dung requirement for a small size of Gobar gas plant per day is 30 kg.
677- The economically smallest size of gobar gas plant is 70 cubic ft.
678- The capacity of biogas plant varies from 2-150 m3.
679- The capacity of smallest biogas plant is about 2 m3.
680- The percentage of nitrogen in gobar gas manure is 2.00%.
681- A quantity of gobar gas required to cook one-person meal is 5 kg.
682- The production of gas from one kilogram of wet dung in biogas plant is 0.037
m3.
683- The pH value of sturry for better gas production should be between 7-8.
684- The gas holder used in floating gas type biogas plant is Inverted drum.
685- In fixed dome type biogas plant, the gas holder is made of Cement and bricks.
686- In floating type biogas plant, gas holder is made of Metal.
687- A high gas production achieved from biogas plant when inside temperature
of the chamber is 35C.

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688- The use of reflector in solar heating devices is to Increase efficiency.
689- A group of solar cell is Solar panel.
690- Chute spillways are used at Steep slope.
691- Chute spillways are constructed at Gully head.
692- Downstream section of straight drop spillway is called as Apron or Stilling
basin.
693- An instrument used for measuring the solar radiation is Pyrheliometer.
694- An instrument, which measures the total or global radiation over a
hemispherical field of view is Pyranometer.
695- A vertical angle of the projection of sun's rays on the horizontal plane and
direction of sun's rays is called Altitude angle.
696- Flate plate collector is generally used for Room heating.
697- The energy wind is converted into Mechanical energy.
698- An instrument used to measure wind speed is Anemometer.
699- Contour trenches are constructed on contour of the land.
700- The first nuclear power station came into operation (1957) at IEA.
701- In biogas plant digestion (biological process) occurs in absence of Oxygen.
702- Biogas is a mixture of Methane and carbon dioxide.
703- The methane bacteria work best at a temperature range of 35-38C.
704- A biogas production starts falling at an atmospheric temperature of 20C.
705- The gas production per unit volume of digester capacity will be maximum
when the diameter to depth ratio of digester will be in the range of 0.66 to
1.00.
706- Solar radiation reaches the earth in the form of Beam and defuse radiation.
707- According to NASA, a standard value for solar constant is 1.353 kW/m2.
708- A contribution of hydropower in total world evergy power is about 6%.
709- The amount of solar energy reaching a specific location on the surface of the
earth at a specific time Insulation.
710- If the pH range of slurry is between 4 and 6 the slurry is Acidic.
711- The solar radiation receives from the sun after its direction has been changed
is Diffuse radiation.
712- The solar radiation received directly from the sun is Beam radiation.
713- The air mass will be one At Zenith.
714- A vertical between the projection of the sun's rays on the horizontal plane
and direction of sun's rays is solar altitude.

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715- A angle through which the Earth must turn to bring the meridian of a point
directly in time with sunrays is Hour angle.
716- The process of removing husk and bran of the paddy in one: operation is
called Hulling.
717- In forced air-dring method the moisture moves from Grain to air.
718- The drying process involves Heat and mass transfer.
719- In thin layer drying, the depth of grain layer should be Less than 20 cm.
720- For air-drying the recommended normal air temperature is 40-50C.
721- The density of wheat is about 998-1238 kg/m3.
722- Angle of repose for paddy ranges between 30-45 degree.
723- The value of angle of repose for wheat is between 23-28 degree.
724- Cyclone separator works on Centrifugal force.
725- Contour trenching is done mainly in Low rainfall areas for moisture
conservation.
726- The law applicable in size reduction of fine powder is Rittinger's law.
727- The moisture content for safe storage corn is about 13 per cent.
728- For seed production, maximum grain temperature usually recommended is
43C.
729- Heat required to evaporate one kg of water from grain is 500 Kcal.
730- The capacity of thermal dryer depends on the Rate of heat and mass transfer.
731- The recommended high temperature limit for seed grains is 80C.
732- Area required to dry one tonne of grain in the sun is about 15 sq. m.
733- Graded terraces are used in the areas of Medium to high rainfall.
734- The total depth of water application to the crop is called Delta.
735- A period in days for which water applied to a crop is Base.
736- When a well is dug in water table aquifer the static water level in the well stands at
Upper elevation of water table.
737- An aquifer found between impermeable layer is Artesian aquifer.
738- The pressure of water in confined aquifer is above atmospheric pressure.
739- In artesian aquifer the elevation to which water level rises in wall is Piezometric
surface.
740- In artesian aquifer, te imaginary surface representing artesian pressure is Piezometric
surface.
741- In semi-confined aquifer, when there is time lag between lowering of two water levels
is Semi-confined aquifer with delayed yield.
742- A perched water-table is a special case of Confined aquifer.
743- Leakage factor is the property of Semi-confined aquifer.
744- Specific yield is the property of unconfined aquifer.
745- The water level stands in the well before pumping is Static water level.

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746- The difference between static water level and pumping water level is known as
Drawdown.
747- The volume of water discharged per unit time is Well yield.
748- A sheet of water, which overflows a weir, is Nape.
749- An open channel flow in which flow characteristic at any poi8nt do not change with
Steady flow.
750- The common conservation measures for agricultural lands are Bunding and broad
based terracing.
751- The velocity of flow in open channel is determined by Darcy's formula.
752- A brick or stone masonry linings are recommended for lining watercourses from
channels where discharge is less than 30 lit/sec.
753- A structure used to carry out irrigation water across the stream, canals, gullies and
other natural depression is Flume.
754- The relative proportion of sand, clay and silt determines Soil texture.
755- The particle size of clay is <0.002 mm.
756- The particle size of silt is between 0.002 to 0.05 mm.
757- To particle size of gravel is >2 mm.
758- The porosity of sandy soil usually ranges from 35 to 50%.
759- The porosity of clayey soil usually ranges from 40 to 60%.
760- The ratio of volume of pores to volume of solids is Void ratio.
761- The density of soil organic matter is usually about 1.3 to 1.5 g/cc.
762- Water that holds highly to the surface of soil particles by adsorption force is
hygroscopic water.
763- Water held by force of surface tension is Capillary water.
764- The capillary water is held between tensions of about 31 atm.
765- The viscosity is measured in Poise.
766- The viscosity of water at 20 degree centigrade is almost 1 centistokes.
767- The tension of water at saturation capacity is almost 0.
768- The moisture content at which the wilting is complete and the plant dies ultimate
wilting.
769- The soil moisture between field capacity and permanent wilting point is Available
moisture.
770- The downward movement of water through saturated or nearly saturated soil is
response to force of gravity is Percolation.
771- The lateral seepage of water in a relatively pervious soil above a less pervious layer is
Interflow.
772- The saturated flow in soil occurs when Water is not under tension.
773- The application of Darcy's Law is limited by the condition that flow through the porous
medium must be Laminar.
774- Darcy's law is applicable when Reynolds number is Less than 1.
775- Symons's gauge is which type of rain gauge Non-recording type.
776- Double mass curve technique is used for checking the Inconsistency of a record.
777- Mass curve of a rainfall of a storm is plotted between Accumulated precipitation and
time in chronological order.
778- A hyetograph is plot of Rainfall intensity versus time.

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779- An isohyetal is a line joining point having Equal rainfall depth in given duration.
780- Chemical that is found to be most suitable as water evaporation inhibitor is to Cetyl
alcohol.
781- Evapotranspiration is confined Day time.
782- Lysimeter is used to measure Evapotranspiration.
783- The lines on a map through places having equal depth of evapotranspiration is called
Isopleths.
784- Settlement of an embankment depends on Void ratio.
785- Interception losses includes Evaporation loss only.
786- Infiltration is measured by the Infiltrometer.
787- The average infiltration rate is called Infiltration index.
788- The science which deal with the measurement of flow is known as Hydrometry.
789- A hydrograph is a plot of Stream discharge against time.
790- Flow-duration curve is plot of Stream discharge against per cen of time the flow is
equaled or exceeded.
791- Flow mass curve is a plot of Cumulative discharge volume again t time in chronological
order.
792- Flow mass curve is an integral curve of Hydrograph.
793- A situation where more than 25% decrease in precipitation from the normal over an
area is called Meteorological drought.
794- When the soil moisture and rainfall are inadequate during the growing season to
support healthy crop growth to maturity is called Agricultural drought.
795- The rising limb of a hydrograph is also known as Concentration curve.
796- A unit hydrograph has One unit of direct runoff.
797- A hydrograph produced by a continuous effective rainfall at a constant rate for an
infinite period is known as S-hydrograph.
798- The hydrological flood routing method used is Equation of continuity.
799- A geological formation which is essentially impermeable for flow of water even though
it may contain water in its pores, is called Aquiclude.
800- An aquifer confined at the bottom but not at the top is called Unconfined aquifer.
801- A geological formation through which only seepage is possible is called Aquitard.
802- A geological formation which is neither porous nor permeable and there are no
interconnected openings hence it cannot transmit water is called Aquifuge.
803- The dimension of the coefficient of transmissibility is L3/T.
804- The specific storgae is Storage coefficient.
805- The discharge per unit draw down at a well is known as Specific capacity.
806- Spattering of small soil particles, caused by raindrop impact on wet soil is called as
Inter rill erosion.
807- In splash erosion the raindrop energy acts in form of Kinetic energy.
808- For attaining a raindrop to terminal velocity, the fall height should be At least 7 m.
809- Soil erosion involves the detachment and transportation of Insoluble soil materials.
810- Soil erosion refers to the gross amount of Soil loss.
811- Soil erosion is more when Raindrop impact along with overland flow.
812- Slope steepness affects more to the Rill erosion.
813- The erosion caused by concentration flow in small channels or rills is called Rill erosion.

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814- The most relevant flow to cause soil erosion is Turbulent flow.
815- Mass movement of soil occurs at Steep slope.
816- Detachability of soil particle increases with decreasing median grain size.
817- V-shaped gullies are found in Hilly areas.
818- Wind velocity varies with Temperature.
819- Surface creep is carried out by the action of Rolling or sliding.
820- Particles less than 0.1 mm diameter is moved by the action of Suspension.
821- A 0.2 mm diameter particles are counted as Saltation particles.
822- Particles size for saltation process ranges from 0.1 to 0.5 mm diameter.
823- Wind erosion is more in Non-cohesive soils.
824- Wind erosion is influenced by Wind velocity, clod size, and surface roughness and soil
moisture.
825- At the wind velocity greater than threshold value, the vibration of particles will be
Zero.
826- Threshold wind velocity is directly proportional to Square root of particles diameter.
827- Stubble mulching is associated with Wind erosion.
828- Splash erosion takes place when rainfall intensity exceeds the Infiltration rate.
829- Gully erosion is the advance stage of Rill erosion.
830- Universal Soil Loss Equation (USLE) is named because It accounts all parameters
affecting the soil loss.

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Drill Machine:
831- Function of seed drill: Seed drill performs the following functions I) to carry
the seeds. ii) To open furrow to a uniform depth iii) to meter the seeds IV) to
place the seed in furrows in an acceptable pattern v) to cover the seeds and
compact the soil around the seed.

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Planter Machine:
832- A planter is a farm implement, usually towed behind a tractor that sows
(plants) seeds in rows throughout a field. It is connected to the tractor with a
drawbar or a three-point hitch. The row units are spaced evenly along
the planter at intervals that vary widely by crop and locale.

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A) Strength of Materials:
1- “Strain”:
(Strain is the response of a system to an applied stress. When
a material is loaded with a force, it produces a stress, which then causes
a material to deform. Engineering strain is defined as the amount of
deformation in the direction of the applied force divided by the initial
length of the material.)
833- Strain is the ratio of change in dimension to original dimension. So it is
dimensionless.
834- The tensile stress is the ratio of tensile force to the change in length. It is the
stress induced in a body when subjected to two equal and opposite pulls. The
ratio of change in length to the original length is the tensile strain.
835- Find the strain of a brass rod of length 250mm which is subjected to a tensile
load of 50kN when the extension of rod is equal to 0.3mm? Strain = dL/L =
0.3/250 = 0.0012.
836- Force = mass x acceleration = kg x m/s2 = N.
837- Creep is the deformation progressively with time. It comes when the body is
subjected to long time load. After the instant deflection due to load, the
deformation occurs slowly with time.
838- Find the strain of a brass rod of length 100mm which is subjected to a tensile
load of 50kN when the extension of rod is equal to 0.1mm? Strain = dL/L =
0.1/100 = 0.001.

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2- “Elasticity”:
(In the science of physics, elasticity is the ability of a deformable body
(e.g., steel, aluminum, rubber, wood, crystals, etc.) to resist a distorting
effect and to return to its original size and shape when that influence or
force is removed. Solid bodies will deform when satisfying forces are
applied to them.)
839- When an external force acts on a body, the body tends to undergo some
deformation. If the external force is removed and the body comes back to its
original shape and size, the body is known as elastic body and this property is
called elasticity.
840- A material can be beaten into thin plates by its property of malleability.
841- The Hooke’s law is valid under the elastic limit of a body. It itself states that
stress is proportional to the strain within the elastic limit.
842- Same elastic properties in all direction is called the homogeneity of a
material.
843- A plastic material does not regain its original shape after removal of load. An
elastic material regain its original shape after removal of load.
844- The body only regain its previous shape and size only up to its elastic limit.
845- Isotropic materials have the same elastic properties in all directions.
846- On reaching the tensile stress to the elastic limit after the proportionality
limit, the stress is no longer proportional to the strain. Then the value of strain
rapidly increases.
847- The elastic modulus is the ratio of stress to strain.

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3- “Hooke’s Law”:
(Hooke's law states that the applied force F equals a constant k times
the displacement or change in length x, or F = kx. The value of k
depends not only on the kind of elastic material under consideration
but also on its dimensions and shape.)
848- Hooke’s law states that strain is directly proportional to strain produced by
the stress when a material is loaded within the elastic limit.
849- For an isotropic, homogeneous and elastic material obeying Hooke’s law, the
number of independent elastic constants is 3 constants Young’s modulus,
Shear modulus and Bulk modulus.
850- Factor of safety is the ratio of ultimate stress to the permissible stress.
851- The proportionality limit is proportional to the area of cross-section. The
material type and loading type will have no influence on the proportionality
limit.

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852- Rubber is generally regarded as a “non-hookean” material because its
elasticity is stress dependent and sensitive to temperature and loading rate.
853- The Hooke’s law is valid only when the stress is proportional to the strain
that is only in the proportionality limit.

4- Stress & Strain Curve:

(In engineering and materials science, a stress–strain curve for a
material gives the relationship between stress and strain. It is obtained
by gradually applying load to a test coupon and measuring the
deformation, from which the stress and strain can be determined.)
854- The elastic modulus is the ratio of stress and strain. So on the stress strain
curve, it is the slope.
855- The relationship between stress and strain on a graph is the stress strain
curve. It represents the change in stress with change in strain.
856- The curve will be stress strain proportional up to the proportionality limit.
After these, the elastic limit will occur.
857- The elastic limit is that limit up to which any material behaves like an elastic
material.

5- Properties of Strain:
858- The ductile material can be drawn into wires because it can resist large
deformation. Malleability is the property by which it can be made into thin
sheets.
859- The stress is the fundamental property because it is calculated in the
laboratory. It is a non-dependable value.
860- The creeping is the phenomenon of deformation in materials which have
been under load for several time. When the load is put on the material,
initially it deforms but when the load is not removed, it causes a small amount
of deformation which increases with time.

6- Strain Energy:
(Strain energy is a type of potential energy that is stored in a structural
member as a result of elastic deformation. The external work done on
such a member when it is deformed from its unstressed state is
transformed into (and considered equal to the strain energy stored in
it.)

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861- Strain energy when load is applied gradually = σ2V/2E.
862- Strain energy per unit volume for solid = q2 / 4G.

7- Resilience:
(In material science, resilience is the ability of a material to absorb
energy when it is deformed elastically, and release that energy upon
unloading. Proof resilience is defined as the maximum energy that can
be absorbed up to the elastic limit, without creating a permanent
distortion)
863- Resilience is the ability of a material to absorb energy when elastically
deformed and to return it. Elasticity is the property by which anybody regain
its original shape. Malleability is the property by which any material can be
beaten into thin sheets.
864- The resilience is the strain energy stored in a specimen so it will be
U = σ2/2E x volume.
865- The modulus of resilience is the proof resilience per unit volume. It is
denoted by σ.
866- The total strain energy stored in a body is commonly known as resilience.
Whenever the straining force is removed from the strained body, the body is
capable of doing work. Hence the resilience is also define as the capacity of a
strained body for doing work on the removal of the straining force.
867- The strain energy stored in a body is equal to the work done by the applied
load in stretching the body.

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8- Center of Gravity:
(The center of gravity (CG) of an object is the point at which weight is
evenly dispersed and all sides are in balance. A human's center of
gravity can change as he takes on different positions, but in many other
objects, it's a fixed location.)

868- The center of gravity of a body is the point through which the whole weight
of the body acts. A body’s center of gravity is the point around which the
resultant torque due to gravity forces vanishes. Where a gravity field can be
considered to be uniform and the center of gravity will be the same.
869- The centroid is the point at which the total area of a plane figure is assumed
to be concentrated. The centroid and center of gravity are at the same point.

9- Moment of Inertia:
(Also called "angular mass" (kg·m2), is the inertia of a rotating body
with respect to its rotation. It is a rotating body's resistance to angular
acceleration or deceleration, equal to the product of the mass and the
square of its perpendicular distance from the axis of rotation.)

870- The axis of reference is the axis about which moment of area is taken. Most
of the times it is either the standard x or y axis or the centeroidal axis.
871- The formula of the moment of inertia is, MOI = ar2 where
M = mass, a = area, l = length, r = distance.
872- The moment of inertia of a circular section is πD4/64.
873- The product of the mass and the square of the distance of the center of
gravity of the mass from an axis is known as the mass moment of inertia about
that axis.
874- The mass moment of inertia of circular plate is Mr2/4.
875- The moment of inertia about x-axis and about y-axis, on the axis they are
zero. So the product of inertia will be zero in the principal axis.

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10- Types of Beams and Loads:

876- A beam is a horizontal structural member subjected to a transverse load
perpendicular to its own axis. Beams are used to support weights of roof
slabs, walls and staircases. The type of beam usually depends upon the span,
type of load elasticity and type of structure.
877- A beam which is fixed at one end and is free at other end, it is called
cantilever beam. The examples for it are portico slabs and sunshades.
878- A beam which is fixed at both supports is called fixed beam or encastered
beam. All framed structures are examples of fixed beams.
879- A Beam extended beyond its support. And the position of extension is called
as over hung portion.

11- Introduction to Shear Force and Bending Moment:

880- As shear force at any section is equal to the algebraic sum of the forces, the
units of the shear force are also in kilo newtons and it is denoted by kN.
881- The bending moment at a section is considered to be negative when it causes
convexity upwards or concavity at bottom, such bending moment is called
hogging bending moment or negative bending moment.
882- A point at which bending moment changes its sign from positive to negative
and vice versa. Such point is termed as point of contra flexure. At this point,
the value of bending moment is zero (0).

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MOMENT OF ENERTIA:

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883- Roller support reaction is normal to the axis of the beam. In case the beam
subjected to trust or to avoid temperature stresses in the beam, one end of
the beam is placed on roller because it facilitate free horizontal movement of
end. It is similar to simple support.
884- As the moment is a product of force and perpendicular distance, the flexural
moment at the support is zero because there is no distance at the support.
885- A hinged support offers resistance against horizontal and vertical movement
but not against rotation. It support offers a vertical and horizontal reaction
only.
886- As the moment is the product of perpendicular distance and force. In
cantilever beam, at its free end the moment will be zero as there is no
distance, but at the fixed end the moment is maximum that is W×l.
887- The maximum bending moment occurs in a beam, when the shear force at
that section is zero or changes the sign because at point of contra flexure the
bending moment is zero.
888- The positive bending moment in a section is considered because it causes
convexity downwards. Such bending moment is called a sagging bending
moment or positive bending moment.
889- At the end supports, the moment (couple) developed is zero, because there
is no distance to take the perpendicular acting load. As the distance is zero,
the moment is obviously zero.

12- Dams:
(A dam is a barrier that stops or restricts the flow of water or
underground streams. Reservoirs created by dams not only suppress
floods but also provide water for activities such as irrigation, human
consumption, industrial use, aquaculture, and navigability.)
890- A dam may be defined as an obstruction or a barrier built across the stream
or river these are artificial storage works. It retains water to create an
impounding reservoir.
891- It is also called a full reservoir level (FRL). It is a level up to which the water
stored obviously the crest of the spillway is fixed at this level.
892- Sluices are openings or conduits extending from upstream face of the dam
to downstream face of the dam. They are used to clean the silt from the
reservoir. They also decrease the peak flood in the reservoir.

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893- It is the total quantity of water stored up to FRL. It includes dead storage also.
It is expressed generally in thousand hectare meter or million cubic meters
(Mm3).
894- It is the lowest level up to which the reservoir is depleted from the
considerations of hydropower generation. So this level is known as minimum
draw down level (MDDL).
895- A gravity dam is that, which is stable against all the external forces achieved
by the weight of the dam itself. This is the most permanent one and hence it
is very commonly used. It may be constructed in all localities.
896- In the dam section, the overturning takes place when a resultant force cuts
the base of the dam downstream of the toe. The factor of safety against
overturning is the ratio of the stabilizing moment to the overturning
moments. The safety against overturning should not be less than 1.5.
897- In the absence of any other forces, the forces due to water and self-weight
of the dam form an elementary profile which will be in triangular section
having zero top width at water level, where the pressure is zero and maximum
base width is at bottom where the maximum water pressure acts.

898- A drainage gallery is an opening in the body of a dam which runs

longitudinally. It runs through the length of the dam. Generally, it is a
rectangle shape with flat a semi-circular head usually 1.5 m wide and 2.5m
height.
899- The joints which facilitate construction of the dam to proceed in small lifts.
These joints are also known as horizontal joints. A lift may be defined as the
vertical distance between two consecutive construction joints. The height is
about 1.5 m each.

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900- Due to variation in temperature it causes contraction and expansion in
masonry or concrete of the dam. It will develop fine cracks in the body of the
dam. By providing contraction joints, these cracks can be avoided.
901- A spillway is the overflow section or portion of the dam over which surplus
discharge flows from reservoir to downstream face. This structure is provided
in the body of the dam or near the dam or on the periphery of the reservoir.
902- By providing sufficient free board and by providing an adequate capacity of
the spillway, failure due to overtopping of the damn can be avoided.
903- By providing berms and turning on the downstream face of the dam, the
failure due to the formation of the gullies can be avoided.
904- The stones used for heavy irrigation works such as dams, bridges, check
dams, weirs, docks should have specific gravity between 2.4 to 2.8. Stones
used for the roof may have less specific gravity.
905- An aquifer is a geologic formation (or) saturated bed which contains water
and yields them significantly. Example: sand bed. They permit the appreciable
quantity of water under ordinary field conditions.
906- The ratio to which the required amount of water is added to weight of
cement to obtain desired consistency and workability of concrete mix is
known as water cement ratio. It varies from 0.42 to 0.48.
907- For no tension to develop in the damn section in any condition, the
eccentricity should be less than b/6. When the reservoir is empty, tension
occurs at toe and compression occurs at heel.

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908- Due to differential settlement cracks may be developed in the bund. These
are of two types 1) longitudinal cracks 2) transverse cracks. The transverse
cracks are more dangerous to the dam section because they can create
concentrated seepage.
909- The water courses are the channel that carries irrigation water to the fields.
The water courses derive their supply from distributaries through outlets.
They are also called as field channels.
910- An outlet is a simple and small irrigation structure which is constructed along
the distributaries. The amount of water that is withdrawn through the outlet
is in proportion to the area that is irrigated below respective point.

13- Slope:
911- The slope is defined as at any point on the bent beam is the angle
measured in terms of radians to which the tangent at that point makes with
the x axis.
912- An elastic curve is defined as the line to which the longitudinal axis of a beam
deviates under given load. It is also called a deflection curve.
913- The slope at any section in a deflection beam is defined as the angle
measured in radians to the tangent at the section makes with the original axis
of the beam. It is denoted by “i”.
914- The slope in cantilever beam is zero at the fixed end of the cantilever and the
slope is maximum at its free end. The slope is determined in the moment area
method through Mohr’s theorems.
915- In this method, the canal is aligned along the falling contour. A generally
higher side is left without bank. So it is also called a single bank canal. The
contour canal cuts across the natural drainage courses.
14- Torque:
(Torque is the measure of the force that can cause an object to rotate
about an axis. Force is what causes an object to accelerate in linear
kinematics. Similarly, torque is what causes an angular acceleration.
Hence, torque can be defined as the rotational equivalent of linear
force.)
916- A cylindrical shaft is subjected to twisting moment or torque when a force is
acting on the member tangentially at some radius in a plane of its cross
section.

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917- Twisting moment will be equal to the product of force and radius. When a
shaft is subjected to a twisting moment, every cross section of the shaft will
surely experience shear stress.
918- As torsion is a product of perpendicular force and radius, the units will be N
m.
Torque is also known as torsion or twisting moment or turning moment.
919- A pump is a mechanical device which converts the mechanical energy into
hydraulic energy. The hydraulic energy is in the form of pressure energy. The
pumps are generally used for lifting liquid from a lower level to a higher level.
920- The ratio of polar moment of inertia to radius of section is called Polar
modulus or Torsional section modulus. Its units are mm3 or m3 (in SI).
921- The polar modulus is a measure of the strength of shaft in rotation. As the
value of Polar modulus increases torsional strength increases.
922- Catchment area can be defined as the area which contributes the surplus
water present over it to the stream or river. It is an area which is responsible
for maintaining flow in natural water bodies. It is expressed in square
kilometers.

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923- Rainfall records are useful for calculating run off over a basin. By using rainfall
records estimate of design parameters of irrigation structures can be made.
The maximum flow due to any storm can be calculated and predicted.
924- Hydrograph is a graph showing variations of discharge with time at a
particular point of the stream. The hydrograph shows the time distribution of
total run off at a point of measurement. Maximum flood discharge can also
be calculated by using hydrograph.

15- Power of Shaft:

(The main purpose of a shaft is to transmit its power to another
member. Let a rotating shaft transmitting power from one of its ends
to another be considered. Let N be the revolutions per minute (rpm),
T be the average torque N · m and ω be the angular speed of the
shaft.)
925- To find power transmitted (P) is P = 2 π N T / 60 watts.
926- The head regulator is hydraulic structure constructed at the head of a canal
system where it takes off from a reservoir behind a weir or a dam. It is used
as a measuring device.
927- Rotodynamic pumps have a rotating element through which as the liquid
passes its angular momentum changes, due to which the pressure energy of
the liquid is increased. The centrifugal pump is a rotodynamic pump.
928- Positive displacement pumps are those pumps in which the liquid is sucked
and then it is pushed to the thrust exerted on it by a piston. The most common
example of the positive displacement pump is the reciprocating pump.
929- Slip of a pump is defined as the difference between the theoretical discharge
and actual discharge after pump.
930- An air vessel is fitted to the suction and delivery pipes at a point close to the
cylinder of a single acting reciprocating. The pump increases the length of the
suction pipe and reduces the work done against friction.
931- Centrifugal pump is used for lifting highly viscous liquids such as oils, muddy
and sewage water, paper pulp etc. In centrifugal pump, torque is uniform and
no air vessels are required.

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16- Strain Energy:

932- The capability of a material to absorb energy when it is deformed elastically
and release that energy upon unloading is known resilience. This resilience is
also termed as Strain energy.
933- By the principle of work, the amount of strain energy in a body is found.
When a load acts on a body there will be deformation, which causes
movement of the applied load. This work is done by the applied load.
934- Long wall short wall method is tedious and long lasting. In this method, the
length of wall running in one direction are measured first out to out and that
of running in the perpendicular direction are measured in to in.

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B) Irrigation Engineering:
1- Types of Irrigation:
935- It is category which comes under Subsurface irrigation as sometimes, water
from leakage of pipes, channels goes underground and causes rise in water
table and this helps in irrigation of crops nearby. Irrigation by natural
processes is called natural sub irrigation.
936- In perennial irrigation, system water is supplied at a constant and continuous
rate from perennial water sources, which get their supplies from melting
snow, in accordance with the requirements of crop. Water is supplied by canal
distribution system using a weir or reservoir.
937- In this system water is first stored at upstream side of the dam for power
generation and then discharged back into the river at the downstream side of
the dam. Thus, sufficient quantity of flow is again available in the river. At a
suitable place in downstream pick-up weir is constructed to divert water to
canals.
938- In direct irrigation system water is directly diverted to the canal without
storing water. For this system low diversion weir or diversion barrage is
constructed across the river. So, this gives the diversion scheme for direct
irrigation system over the other systems of irrigation.
939- In lift irrigation system mechanical means are used to supply water to the
crops for irrigation. This is quite the case of wells where by mechanical means
water is supplied for irrigation.
940- Flow irrigation is the type of irrigation in which supply of irrigation water is
merely conveyed onto the land by the gravity flow or gravitation. In other
words, water is supplied from higher grounds to lower grounds.
2- Techniques of Water Distribution in the Farms:
941- In the drip irrigation method, it involves laying a system of head, mains, sub-
mains, laterals, and drip nozzles. From these nozzles, water oozes or trickles
out at a small rate into the plant roots area. Hence the name trickle irrigation
method.
942- In free flooding method is done, by dividing the entire land to be irrigated
into a number strips called laterals. These laterals may be perpendicular to
the sides of the field or perpendicular to the contour lines. So, as this method
uses contour lines of field it is suitable for both flat lands and steep lands.

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943- In border flooding uses borders to divide the land into strips of with 10 to 20
meters, 100 to 400 meters in length each. Ridges are provided between
borders so as to prevent overtopping during irrigation. Supply ditches run
perpendicular to borders either on one side of the field to provide water for
irrigation.

DRIP IRRIGATION:

SPRINKLER IRRIGATION:

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SURFACE IRRIGATION:

SUB-SURFACE IRRIGATION:

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944- In the sprinkler irrigation, water is applied to the field through a network of
pipes connected to sprinklers of different types, and through these
sprinklers, water comes out as artificial rain and waters the crops in the
field.
945- In furrow method only one half to one fifth of the surface of land is wetted
so as to reduce the evaporation losses. In other methods, evaporation losses
cannot be controlled properly.

3- Water Requirements – Crop Period or Base Period:

946- Crop period is the time period that is elapsed from the instant of sowing to
that of harvesting. Kor period is the time elapsed for kor watering. The base
period is the time elapsed from first watering to the last watering.
947- Kor period depends upon the climate. It is generally less for humid climates
and more for dry climates. Crop type, length of the base period, the water
requirement of plants at different stages, soil conditions, etc. are all factors
influencing the number of watering.
948- Before sowing a crop first watering has to be done on the land to add
sufficient water to the unsaturated zone of a soil which is required for the
initial growth of the crop. This watering is known as Paleo.
949- Intensity of irrigation can be defined as “a ratio of irrigated land at a time
one crop season to C.C.A”. Mathematically, Area to be irrigated = C.C.A x
intensity of irrigation.
950- A part of the water that will move out of the soil, if proper drainage is
provided, is known as gravitational or superfluous water. This is not useful for
the plants and it cannot be absorbed by the root zone.
951- Capillary water exists in the porous space of the soil by molecular attraction.
This is the useful moisture for the growth of plants. Hydroscopic water and
gravitational water cannot be absorbed by the root zone.
952- An area where irrigation is a must is the arid region. The crops that are able
to survive semi-arid regions are maize, beans, green grams.

4- Water Requirements – Duty and Delta of a Crop:

953- Every type of crop requires different amount of water for its complete
growth in certain fixed intervals of time. The time interval between two
consecutive intervals is called a rotation period.

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954- The total quantity of water required by the crop for its complete growth can
be expressed in terms of depth of water standing on the field. This total depth
expressed in cm is called delta.
955- Duty of water gives a relation volume of water required and the area of
irrigated crop. So, in this way if we know the area of crop irrigated we can
know discharge required for the channel.
956- When direct irrigation is used, then the units of duty, always expressed in
hectares/cumec. Then duty is called flow duty.
957- Gross Commanded Area (G.C.A) is the sum of Cultivable Commanded Area
(C.C.A) and uncultivable area. Again Cultivable Commanded Area (C.C.A) is
divided into the sum of cultivable cultivated and cultivable uncultivated areas.
Therefore, Gross Commanded Area (G.C.A) is a large quantity.
958- By lining of canals, carrying irrigation supplies we can reduce seepage and
evaporation losses. Therefore reducing the field requirement of water
increases the duty.
959- As water flows from river to subsequent parts of the canal system some
water losses takes place due to evaporation, and percolation. Due to this, the
duty of water goes on increasing from starting point of canal system till its
end point. Therefore, the duty of water is more at the last point of the system,
i.e. head of the water-course.
960- The yield increases with water, reaches a certain maximum value and then,
falls down. The quantity of water at this maximum value is called optimum
water depth.
961- Root zone depth is the maximum distance below the surface of the soil from
which a particular crop derives water for use and develops its root system. It
usually depends on soil type, subsoil formation, kinds of crop grown, the
distance of water table from the ground surface, and amount of water
supplied during irrigation.
962- Clayey soils do not permit crop roots to penetrate to considerable depths.
Hence, for clayey soils, the depth of root-zone is less.

5- Water Requirements of Crops – Irrigation Efficiencies:

963- The water application efficiency is the ratio of water stored in the root zone
to the water actually delivered to the field. It takes into consideration the
water lost in the farm hence, it is also known as on-farm efficiency.

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964- It is the ratio of water delivered into the fields to the water entering into the
channel. This efficiency accounts for the conveyance or transit losses.
965- Leaching is the supply of additional water to wash away the salts in a saline
prone area. The presence of excess salts in water requires high water storage
efficiency in order to keep the salts washed out of the soil.
966- Efficiency is inversely proportional to the losses. If losses are more, the
output is less and therefore, efficiency is less.
967- Water distribution efficiency is also known as the uniformity coefficient. It is
the measure of how uniformly water is applied to the area being irrigated.
The effectiveness of irrigation is measured by its uniformity coefficient.

6- Water Requirements of Crops – Consumptive Use of

Evapotranspiration:
968- Consumptive use is defined as the total amount of water used by the plants
in transpiration and evaporation from soils, in specific time. So, therefore the
values of consumptive use vary for different crops, and vary for same crops
at different places or times.
969- Transpiration is the process of the plant through which water leaves the
plant, through its leaves as water vapor and enters the atmosphere.
970- Photosynthesis is an important process of the plant through which the plant
produces carbohydrates for its growth, and it is during this process
transpiration occurs as an integral process in the whole photosynthesis
process.
971- Water enters the leaves of the plant through the roots, where
photosynthesis happens. During this, air enters the stomata of the leaves. The
protein chloroplasts present here takes the carbon dioxide in air and uses it
to produce carbohydrates.
972- Preparation of food, i.e. carbohydrates is done during daylight alone, as
photosynthesis process occurs only during sunlight. Therefore most of the
transpiration occurs during the day alone.
973- Transpiration ratio is directly proportional to water requirement of the plant.
So, therefore if amount of water increases the ratio increases, and if amount
of water decreases the ratio decreases.
974- Potential Evapotranspiration (PET) involves transpiration process. As this
process consists of transpiration losses through leaves of plant, and

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evaporation losses from surroundings of the plant and this directly dependent
on availability of moisture which when is sufficiently available to meet the
needs of the vegetation then it is called PET. Therefore this clearly states PET
critically depends on climatological conditions.
975- Actual Evapotranspiration (AET) is actual and real evapotranspiration that
occurs in any specific situation of the field. The specific situation of the field
directly depends on the characteristics of soil and the type of vegetation
present in that particular soil. So, therefore AET indirectly depends on the
characteristics of soil and vegetation, in the field.
976- Actually lysimeter method is used to determine the AET. This method
consists of a tight tanker filled with a block of soil and is installed in a field of
growing plants. The conditions to maintain this tanker on par with conditions
of the field and the measurement of water added to the tanker to maintain
moisture content are time-consuming and costlier field studies.

7- Water Requirements of Crops – Effective Rainfall:

977- Effective rainfall is that portion of precipitation that remains in the soil and
is available for consumptive use. It is available to meet the evapotranspiration
needs of the crop and does not include percolation losses and surface runoff
losses.

978- Field irrigation requirement (FIR) can be defined as the water required
meeting the net irrigation requirements plus the amount of water lost as
surface runoff and through deep percolation. Mathematically, FIR = NIR /
Na where Na = application efficiency and NIR = Net irrigation requirement.
979- Net irrigation requirement (NIR) can be defined as the amount of irrigation
water required to be delivered at the field to meet the evapotranspiration
and leaching losses.
NIR = (Cu – Re) + amount of water required for leaching = CIR + leaching losses
requirement.
980- Gross irrigation requirement defined as the amount of water required to
meet the field irrigation requirements plus the amount of irrigation water lost
in conveyance through the canal system by evaporation and seepage.
Mathematically, GIR = FIR/Nc.

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8- Water Requirements of Crops – Soil-Moisture-Irrigation

Relationship:
981- When water flows over the land, some water is absorbed in the root zone
and remaining water flows underground due to the action of gravity, hence
the name gravity water.
982- Immediately after application of irrigation water or sudden rain the gravity
water drains down to the water table. But certain amount of water gets
retained on the surfaces of soil grains and this water cannot be easily drained
under action of gravity. This water is called field capacity.
983- Generally field capacity is defined as the water content of soil that is left after
free gravity drainage for certain period of time. This period of free gravity
drainage is generally taken as 2 to 5 days.
984- Due to these forces like molecular attraction between adjacent soil grains
and by their loose chemical bonds, i.e. adsorption, the soil grains are able to
retain water against the action of gravity on their surfaces.
985- Capillary water is that part of field capacity water, which is attached to the
soil molecules by surface tension against the gravitational forces.
986- The water which is attached to the soil molecules due to the influence of
their loose chemical bonds is called hygroscopic water. This is a part of field
capacity water.
987- The capillary water can be extracted by the plants by capillary action or
capillarity. But, hygroscopic water cannot be extracted by the capillarity.
988- At permanent wilting point plants can no longer extract sufficient water for
its growth and wilts up. Plants are able to extract water from the soil till this
point is reached. This is the point at which permanent wilting of plants take
place.
989- The amount water available to the plants is the difference between field
capacity water and permanent wilting point water. This amount of water is
known as Available moisture or maximum storage capacity of soil.
990- Readily available moisture is that part of available moisture which can be
easily extracted by plants and of 75 to 80% of available moisture.
991- Soil moisture deficiency is the water that is required to bring the soil
moisture content of a given soil to its field capacity. It is also known as field
moisture deficiency.

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9- Canal Irrigation System – Alluvial and Non-alluvial Canals:

992- The process of silt deposition over a long period of time resulting in the
formation of soil is called alluvial soil. It has a flat surface slope and even area.
Hard foundations are generally not available in this kind of soil.

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993- The disintegration of mountainous rocks over a period of time resulting in
the formation of a rocky plain area called non-alluvial soils. It has uneven
topography and hard foundations are available in this soil.
994- Direct irrigation using a weir or barrage (canal irrigation) is generally
preferred in alluvial soil as compared to storage irrigation. Alluvial soil is a
fine-grained fertile soil and due to its porosity and texture provides good
drainage making it highly productive and suitable for agriculture.
995- A feeder canal is used to feed another canal and no direct irrigation is carried
out from it. A protective canal is constructed to provide employment in the
famine-affected area. A lined canal is provided with a lining of impervious
material to prevent the seepage of water. A contour canal has to cross the
drainage and hence, cross drainage works are required.
996- An inundation canal is a canal which gets its supplies only when the water
level in the river from which it takes off rises during floods. They obtain their
supplies through open cuts in the banks of the river.
997- A navigation canal is constructed to provide various navigation facilities. The
velocity of flowing water should be small for easy movement of small ships
and barges in the direction of flow of water as well as in the opposite
direction.
998- A permanent canal is the one that is fed by a permanent source of supply.
The provision of permanent regulation and distribution works is made in the
permanent canal. It is further classified as Perennial canals and non-perennial
canals.
999- A carrier canal is a canal used for both direct irrigation and for feeding water
to another canal. Thus, it acts as an irrigation canal as well as a feeder canal.
1000- Non-alluvial soils are formed by the disintegration of mountainous rocks.
Due to its uneven topography and rocky mass formed after disintegration,
hard foundations are generally available.

10- Canal Irrigation System – Alignment:

1001- Side slope canal is that type of canal which runs perpendicular to the ground
contours, i.e. they run parallel to natural drainage flow and do not intercept
the drainage channels and therefore avoiding the construction of cross
drainage structures.

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1002- The dividing line between the catchment areas of two streams is called ridge
or watershed. The main watershed between two streams divides the drainage
area of the two streams.
1003- For flat lands, the slopes are relatively flat and uniform and it is very easy,
and advantageous to align canals along watershed. Therefore the name of the
alignment is watershed canal.
1004- By aligning a canal on the ridge, helps to irrigate the land on both sides of
the canal. Moreover, the drainage flows away from the ridge, this gives an
advantage in a way that the drainage does not cross a canal aligned on the
ridge. Therefore the cost of construction of cross drainage works is reduced.
1005- The maintenance of field channel is the responsibility of the farmers
because this channel is laid along the field boundaries and supply water to
the fields to meet their requirements.
1006- When a channel is aligned the proposed curve should be as gentle as
possible. It leads to silting on the convex side and scouring on the concave
side due to the disturbance of flow caused by curves. Stone pitching is
sometimes proposed to avoid erosion and scouring.

11- Canal Irrigation System – Losses of Water in Canal:

1007- Seepage and Evaporation are the two main reasons for loss of canal
discharge. Out of these, seepage loss is most significant in the initial stages
(about 40%). Evaporation loss may range from 2 to 3% of the total canal
discharge.
1008- The loss due to seepage is the most significant so far as irrigation loss from
canals is considered. The porosity of the soil, underground water-table
condition, condition of the canal system, and physical properties of the canal
water are all factors affecting seepage loss.
1009- Seepage loss is generally measured by Inflow and Outflow method. Regular
and simultaneous discharge measurement is done at the entrance and end of
the selected reach. Same gauge and discharge are maintained at the entrance
during the period of observations. The difference between the inflow and
outflow over the reach gives the quantity of water lost.

12- Design Capacity for an Irrigation Canal:

1010- Suppose take wheat crop for example, let us say it requires a 60 cm of water
in a total period of about 240 days (for a given area of field) thus giving an

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average outlet factor of 3456 hectares/cumec. But the kor depth of wheat is
14 cm in about 4 weeks which gives an outlet of 1728 hectares/cumec.
Therefore it is clear that for a given area (A) outlet factor of 1728 is very much
more than 3456. Hence kor demand should be given importance while
designing irrigation canal.
1011- The water depth will be multiplied by crop area which is required in this
interval, so as to give the volume of water required in this interval. By dividing
the volume by interval, we can find out the discharge needed for each
interval. The summation of this will give the discharge required for all the
crops in each interval. The canal can then be designed for the maximum of
these values.

13- Sediment Transport – Mechanics:

1012- Coherent means that there is a cohesive force between particles such as in
the case of clays. The soil is assumed to be incoherent so that each soil grain
is studied individually. Most of our river beds are made up of gravels and
sands in which there is no cohesion.
1013- The force exerted by water in the direction of flow is the drag force or
tractive force. If this force on the bed particles exceeds the force opposing
their movement then, the bed particles will start moving to lead to the
sediment transport.

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1014- Shield was the first person to analyze the experimental data on incipient
motion condition using the critical tractive force approach. The assumption
of the entry of clean and clear water in the channel is used to develop non-
scouring highest possible flow velocity at the peak flow.
1015- The unit tractive force in channels is uniformly distributed along the wetted
perimeter. For the bed of the canal, the average shear stress is equal to the
tractive force per unit area. For side slopes of the canal, average shear stress
is equal to 0.75 times the tractive force per unit area.
1016- The direct accurate mathematical solution based on the resistance
equations given by Chezy’s formula and Manning’s formula is very
complicated in Pakistan based alluvial channels. So, therefore hypothetical
theories given by Kennedy and Lacey are used, as these theories are based on
experiments and experience from existing channels over the years.
1017- The given velocity of flow of a channel and certain depth can carry in
suspension, some amount of silt. But if the velocity is more and depth is not
fully charged with silt it will erode the bed and sides of the channel. And if the
velocity is less, the silt cannot be carried in suspension by the flow, hence it is
dropped.
1018- Scouring is not a rare phenomenon in channels. It is very understandable
and can be controlled or avoided by proper designing of channels. Scouring
causes loss of command in channels and lowers full supply level of channel.
This causes breaching of canal banks and in turn causes failure of foundations
of irrigation structures.
1019- The silting problem is very common in any kind of artificial channels, or we
can say there is no natural or artificial channel with the silting problem. Silting
interferes with the proper working of a channel, as it causes reduction in the
channel section due to siltation, which thereby reduces the discharge capacity
of the channel.
1020- The channel is said to be in regime state, when the flow of the channel is
such that silting and scouring effects need no special attention. This state is
not easy to achieve in rivers but can be achieved in artificial channels, by
proper designing of the channels.
1021- The basis for designing a channel to be in regime state, whatever the
amount of silt has entered the channel has to be kept in suspension, so that
it does not settle down and get deposited in the channel anywhere. And the

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velocity of the flow in the channel should be such that it does not produce silt
by eroding the banks and beds of the channel.
1022- The quantity of sediment load entering the channel from the head works
plays an important role in designing the regime channels, as it controls the
cross-section and shape of the regime channel. Moreover the design of
regime channel is not complete until provisions are made for the effects
produced by the actual quantity of sediment load present in the channel.
1023- From the observations of Kennedy’s research, he concluded that the silting
action in channels is due to the generation of eddies, rising to the surface.
These eddies are in turn generated by the friction of flowing water with the
channel surface.

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1024- Eddies affect the formation of silting action in a channel brief investigation
shows that the vertical component of these eddies try to move sediment up
and the weight of sediment tries to bring it down, thus keeping the sediment
in suspension. So, silting is avoided if sufficient velocity is generated to form
eddies and keep the sediment in suspension. This velocity is called critical
velocity.
1025- For a channel to be in regime condition it should not have silting and
scouring action. To obtain this the silt entering the channel must be carried
away through the channel, by the channel section. The artificial channel to be
in a regime it must have a fixed slope and fixed section. So, therefore to
achieve this flow in the channel should uniform flow.
1026- The sediment carrying capacity will reduce if the width of the river increases as
the discharge per unit width will decrease. The deposition of the sediment will start
which will increase the bed slope.
1027- In turbulent flow, momentum transfer or mass exchange takes place due to the
jumping of particles from higher velocity region to lower velocity region. Due to this
transfer of momentum between two adjacent fluid layers, effective shear stress is
caused at the interface between the layers.

14- Cross-Section of an Irrigation Canal:

1028- Flatter slopes such as 1 : 1 and 1.5 : 1 are also constructed at the time of
execution, but actual capacity of channel is worked out in 1/2 : 1 slope
because even if we provide 1 : 1 or 1.5 : 1 slope the silt gets deposited on this
slope and gives a new side slope 1/2 : 1. Therefore the actual capacity is
calculated using 1/2: 1 slope.
1029- The side slopes of a canal are designed such that they are stable, depending
upon the type of soil present in canal area. A canal in cutting is provided with
steeper slope than a canal in filing, as the stability of soil is more in case of
canal in cutting than in canal in filing.
1030- Berm is the horizontal distance between the toe of the bank and top edge
of the cutting. If s2 : 1 is the slope in filling and s1 : 1 is the slope in cutting, and
the initial depth of the berm from the bed of the canal is d1 then width of the
berm is (s2 – s1) d1. As d1 varies, the width of the berm also varies. As siltation
occurs the formula is (s2:1/2) y (y=over all new depth of the berm).
1031- The silt which gets deposited is very fine and impervious therefore it acts as
a good lining which reduces losses, leakage, breaches etc. This also gives

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strength to the banks and protects them against erosion and breaches. This
deposition also provides scope for future widening of the canal.
1032- The main purpose of the banks is to retain water in the canal itself. This
retaining action is always needed, in cases of low availability of water or
during the period of floods. The other purposes of the banks include a means
of communication and inspection paths.
1033- A structure of 0.3 m high and 0.3 to 0.6 m wide is provided along the banks,
with side slopes of 1.5: 1 to 2: 1. This structure is known as dowlas. They also
help in preventing soil erosion during rains.
1034- Berms provide a path for inspection. Excessive loss of water due to seepage
is checked. It is so because berms are formed of fine silt which makes berms
fairly impervious.
1035- Breaches are the gaps created in the canal banks due to breaking up of the
banks. The maintenance of service roads includes removal of grass and small
bushes, levelling and surfacing of roads. The slopes if damaged should be
repaired to facilitate drainage of roads.
1036- Internal silting method is adopted only when new canals are constructed as
the section has to be sufficiently wide. In the external silting method,
subsidiary banks are constructed to hold the water externally in a confined
position. Both of these are methods of strengthening of canal banks.
1037- It is very essential to bring the flow of water out of the channel section to
accomplish silting of banks externally. Subsidiary banks are required to hold
the water externally in a confined position and are constructed parallel to the
canal main banks.
1038- Berm is a narrow horizontal strip of natural ground left between the canal
section and inner toe of the bank. This is provided in such a way that the bed
line and the bank line remain parallel.
1039- If lining is not provided in the canal then irrigation water is lost in the form
of percolation and absorption as seepage losses. This loss is very significant
as it reduces the potential of the irrigation water, which is a costly commodity.
So, in order to reduce seepage losses the lining of the canal is needed.
1040- Due to uncontrolled seepage losses the water in the canal gets percolated
and the water table level in underground rises. This level rises up to or near
the ground level. This renders the land unfit for agriculture as the crop roots

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bring up the alkali salts to the ground level. This phenomenon is known as
waterlogging and the land is called Thur.
1041- With the help of lining canals can be designed for both in smaller cross
section and shorter in length. Steep gradients can be provided as higher
velocities are allowed, and flat slopes can also be provided without silting
action on lined canals. Therefore, due to these reasons the command area
can be increased.
1042- The reason is very simple. The lined surface provides a smooth surface for
the flow of water with minimum resistance, whereas the unlined canal
provides more resistance due to vegetation, undulations, rocks etc. Moreover
the velocity of flow in lined canal is high when compared with the velocity in
unlined canal, as the capacity of canal is dependent on the velocity directly if
velocity increases so does the capacity of the canal.
1043- Coefficient of roughness is indirectly proportional to velocity in any
mathematical formula, or condition, or equation. So, therefore the value of
this coefficient is more for unlined canals than the lined canals. Hence the
velocity is more for lined canals than the unlined canals and therefore
capacity for lined canals is more.
1044- Floods are catastrophic disasters in nature. If a canal is not lined or it
constructed on weak foundations then there is chance of regular floods,
sometimes even flash floods. In unlined canals there is constant eroding of
embankments which ultimately leads to floods. So, therefore lining of canal
helps to keep a check or stop the floods, which is a major danger.
1045- The construction of larger reservoirs and bigger dams will be necessary if
there is heavy seepage loss in canals. Lining the canals reduces their
impounding capacity and hence lower the construction costs of these works.

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15- Channel Cross-sections:

1046- Generally, Triangular and Trapezoidal channel sections are adopted.
For smaller discharges, the Triangular channel section is adopted and
trapezoidal channel for larger discharges.
1047- The vertical distance between the full supply level (F.S.L) and the top of
the bank is called freeboard. It depends on the size of the canal, location of
the canal and water level fluctuations.
1048- Brick Lining is very popular in Pakistan due to bricks can be laid by
ordinary masons, rigid quality control is not needed, expansion joints are not
needed, huge employment is provided, isolated damaged parts can be easily
repaired, plastering of bricks can be done to increase the canal capacity and
its life span also.
1049- This type of lining is only used for lining the side slopes of the canal by
proper placing and packing of stones, either after laying a filter paper or not,
depending on the soil requirement. Therefore this lining does not help in
preventing the seepage losses but helps to maintain the shape of the canal,
hence reducing the maintenance cost.
1050- The mixture ratio of M15 grade is 1:2:4 (cement, sand, coarse
aggregate) and this ratio is a good quality type for construction of cement
concrete lining. This lining gives satisfactory service, high durability, hydraulic
efficiency, weed free surface, long life, minimum maintenance cost.
1051- Curing is mainly done because the concrete which is laid for the lining
gains hardened properties over time. After laying the concrete lining a period
of 24 to 36 hours gap is given before curing starts. Curing process is done for
a period of 28 days. On the canal bed it is done by constructing 150 mm deep
earthen bunds across, so that water stands regularly on the bed. On the side
slopes it is done by constructing masonry weep holes.

16- Salinity and Water-logging:

1052- A land is said to be water-logged when the productivity of land gets
affected and the crop root-zone gets deprived of proper aeration due to the
flooding or high water table. It represents a saturated condition of the soil
especially that of the crop root-zone with water. It also leads to the salinity of
the soil.

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1053- Presence of excessive moisture lowers the temperature of the soil. In
low temperatures the bacterial activities are retarded and their growth rates
are also affected. It affects the soil-crop badly as soil microbial activity is
disturbed.
1054- By observing variations in the ground-water level is one of the ways of
keeping a check on the problem. It can be done by measuring the depth of
water levels at regular intervals in the wells dug in the area.
1055- Hydrologic equation:- Inflow = Outflow + Storage
Inflow represents the amount of water that enters the sub-soil in various
processes. The term outflow represents mainly evaporation from the soil,
transpiration from plants, and underground drainage of the track. The term
storage represents a change in the ground-water reservoir.
1056- The normal cultivation operations such as tilling, ploughing is difficult
in wet soils. The cultivation operation becomes impossible if the free water
may rise above the surface of the land in extreme cases. Such land is called
swampy land.
1057- Due to efflorescence, there is a deposition of salts on the surface of soil
forming a thin crust after the evaporation of water. Land affected by that is
saline soil and the soil water surrounding the roots of the plants reduces the
osmotic activity of the soil.
1058- Installation of lift irrigation system is one of the remedial measures
adopted to reclaim the water-logged area and others are preventive
measures which keep the land free from water-logging. It is found to be a very
effective method of reclaiming water-logged land.
1059- The various factors that contribute to the rise in water table i.e.
water-logging are –
• Over and intensive irrigation
• Seepage of water through canals and adjoining high lands
• Inadequate natural drainage and surface drainage
• Excessive rains and submergence due to floods
• Impervious obstruction.
1060- Contour bunding or contour farming is the sustainable land
management practice of planting or farming across a slope. The following
are the measures adopted for controlling waterlogging are –
• Canal lining

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• Crop rotation and optimum use of water
• Provision of intercepting drains
• Reducing the intensity of irrigation
• Improving the natural drainage system and providing an efficient drainage
system.
1061- In hilly areas, the water is drained quickly, but in case of flat or irregular
terrains having depressions the drainage is not adequate. This leads to more
stagnation of water causing percolation and rising of water table.
1062- During rains storm water gets mixed with irrigation water. The
irrigation water should be removed so as to not mix with storm water as this
leads to percolation. Moreover, if proper drainage is not present constant
percolation happens and water table rises.
1063- Generally, water after seeping the soil moves horizontally before even
seeping further. But this movement is sometimes is obstructed by some
obstructions like stone, ice, or some impervious stratum below the top layers
of pervious soil. In these cases seeping water cannot go deep and resulting in
the rise of water table.

17- Reclamation of Saline and Alkaline Lands:

1064- Na2CO3 is present in excess in black alkali soils. It is known as a black
alkali because it dissolves some organic constituents of soil which appears
black in solution with it. The patches of black stain are generally spotted on
the ground.
1065- NaCl is found in excess in white-alkali soils. In this, salinity is caused by
soluble salts other than alkali salts. The reaction between NaCl and soil (S)
produces Na(S) and Cl– ion and the soluble products are leached away from
the soil surface by drainage water.
1066- The plant roots contain pure water on one side of the membrane and
highly concentrated salt solution on the other side. By osmosis, the pure
water within the roots will start flowing out of the roots towards the salt
solution until the pressure becomes equal.
1067- Alkali soils are best reclaimed by cationic exchange i.e. replacement of
alkali from soil colloids by calcium ions. Application of gypsum in the soil
reduces alkalinity to a great extent and makes the soil fertile. Good drainage
leaches away the by-product of the reaction.

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1068- If the salt concentration is less than 0.5 g/L, then there is no salinization
risk and no restriction on the use of irrigation water. If the concentration is
more than 2 g/L, there is high risk and is not generally advised for use. If the
concentration is in between there is slight to moderate risk and it should be
used with appropriate water management practices.
1069- The three classes are –
i. Saline or white alkali or soil- High soluble salts and low ESP
ii. Alkali or Sodic or black alkali soil – Low salt content but high ESP
iii. Saline-alkali soils – High salt content and High ESP.

18- Diversion Head Works – Weir and Barrage:

1070- According to the material used and certain design features, the gravity
weir is sub-divided into three groups. They are vertical drop weir, sloping
weir, and parabolic weir. Sloping weir is again classified into two groups,
namely masonry slop weir and dry stone slope weir.
1071- In gravity weir, the uplift pressure is due to the seepage of water below
the floor and is resisted entirely by the weight of the floor.
1072- In non-gravity type weir the thickness of the floor is relatively kept less,
and the uplift pressure is largely resisted by the bending action of the
reinforced concrete floor.
1073- Vertical Drop Weir is suitable for kind of foundation because it is
provided with or without crest gates, cutoff piles are provided at both
upstream and downstream, to protect against scouring aprons are provided
at both up and down streams, and at downstream to relieve uplift pressure
graded inverted filter is provided.
1074- Weir is an obstruction across the river to raise its water level and divert
into new channel. It can also store water for short duration of time of short
supplies, known as storage weir. The only main difference between dam and
weir is that dam can store water comparatively for longer duration than weir
and the dam is at more height than the weir.
1075- Barrage is almost a similar structure like a weir, but the difference is
that barrage is not a solid obstruction across a river and moreover the heading
of the river is controlled by gates alone. The crest level in barrage is kept at
low level. During floods the gates are kept for discharge of excess waters and

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when the flood recedes the gates are lowered, thus solving the silting
problem.
1076- Mainly four causes are responsible for the failure of weirs. They are
piping, rupture of floor due to uplift, rupture of floor due to suction caused
by standing wave, and scouring at the upstream and downstream side of the
weir floor.
1077- In Gravity weir, the weight of the weir balances the uplift pressure
caused by the seepage water. In non-gravity weirs, the weight of the concrete
slab and the divide piers together keep the structure safe against the uplift.
1078- The diversion head work is generally divided into eight component
parts, namely weir, divide wall, fish ladder, pocket or approach ladder,
scouring sluices, silt prevention devices, canal head regulator, and river
training works.
1079- In order to find an appropriate location for the head work on the river,
the river is divided into four stages. They are mountainous stage, boulder
stage, alluvial plain, and delta stage.
1080- Before the start of monsoons the fish migrate to the upstream in search
of warm water. So, therefore some provision is made to make some space
available for them to travel. And this achieved by the construction of fish
ladder as they provide the room for movement and also slows down the flow
for easy traveling of fish.
1081- As the name itself suggests (regulator) head regulator helps in
regulating the supply of flow easy in a canal, controls silt entry into the canal,
and shut river floods.
1082- Silt excluder is placed in front of the head regulator by which the silt is
removed from the water even before the water enters the canal. The
fundamental principle on which this device acts is the fact that stream
carrying silt in suspension, the concentration of silt charge is more in upper
layers than in lower layers. Therefore this device is so designed for separating
these two layers without disturbance.
1083- This device can be called as a failsafe device in case the silt excluder
does not work properly or the silt charge is beyond the capacity of the silt
excluder. This device removes or ejects or extracts the silt which has entered
the canal and is thrown out. This device placement is a curative measure and
is constructed at some distance from the head regulator.

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1084- Three river training works are needed on the canal head works, to
prevent the river from outflanking the works due to a change in its course and
ensure smooth and an axial flow of water. The works include guide banks,
marginal bunds, and spurs. Guide banks force the river into the restricted
channel, thus ensuring smooth and axial flow near the weir site. In order to
protect the area from submergence due to raise in HFL these marginal bunds
are provided. The spurs are the works that protect the marginal bunds.
1085- The discharging capacity of an under sluice is fixed by the
considerations like to ensure proper scouring and its capacity should be
double the canal discharge, sluices should of sufficient capacity to discharge
winter freshlet, and during floods 10 to 15 percent of maximum flood
discharge should be done.

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19- Hydraulic Jump:

1086- Undular Jump is small the water shall not rise suddenly but will pass
through a number of undulations.
1087- In certain cases when the jump is high, then the difference in a jump is
large and it occurs suddenly or abruptly.
1088- According to Froude number from 1.7 to 2.5 a series of rollers develop
on the surface of the jump, but at the downstream side the surface is smooth.
The energy loss is low and a uniform velocity is maintained. The jump under
these conditions is called a weak jump.
1089- When the value of Froude number is 9 or more, then the energy
dissipation reaches up to 85% in the flow. The jump under this condition is
called strong jump.
1090- According the values of Froude number (F1) the jumps are classified
into six groups. Namely, no jump for F1 = 1, for F1 = 1 to 1.7 the jump is undular
jump, for F1 = 1.7 to 2.5 the jump is weak jump, for F1 = 2.5 to 4.5 the jump is
oscillating jump, for F1 = 4.5 to 9 the jump is steady jump, and for F1 = 9 or
above the jump is strong jump.
1091- For the value of Froude number from 4.5 to 9, when the performance
of the jump is best, when the jump is well balanced and the energy dissipation
is from 45 to 70%, then the jump is called a steady jump.

20- Canal Falls:

1092- If the available natural slope is steeper than the bed slope of the canal,
then this is adjusted by the construction of vertical falls or drops in the canal
bed at suitable intervals. But such a drop will not be stable, therefore in order
to maintain this drop a masonry structure is constructed. This is known as
canal fall or canal drop.
1093- By considering the commanded area of a branch canal or a distributary
canal the location for the falls is decided. The procedure is to fix the FSL
needed at the head of the off taking channels and outlets. Thus the FSL can
be marked at all commanded points and hence deciding appropriate locations
for the falls in canal FSL and therefore in canal beds.

21- Canal Regulation:

1094- The water enters the main canal from the river and this water has to
be divided into different branches, distributaries in accordance to the relative

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demand on these different channels. Therefore this process of distribution of
water is called as canal distribution.
1095- The discharge value of water has to be adjusted to any value necessary
to distribute the water effectively. This is done with the help of regulators.
1096- Canal regulation works are the structures constructed in order to
control and regulate the discharges, depths, and velocities in the canals.
These structures ensure the efficient functioning of the irrigation canal
system.
1097- There are five types of canal irrigation works, namely canal falls, canal
regulators, canal escapes, metering flumes, and canal outlets and modules.

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1098- The main functions of a head regulator are to control and regulate the
water entering the off take channel, to serve as a meter for measuring
discharge, and to control silt entering into the off take channel.
1099- The conditions are considered for the worst conditions of the flow. The
flow of the canal should be taken as it is when there is full supply of discharge
down the channel with all gates of both head and cross regulators fully open.
The discharge in the main channel is low but in the off take channel is running
full, the FSL is maintained by partial opening of the gates of cross regulator.
1100- The canal escape is a side channel constructed to remove surplus
amounts of water from an irrigation channel such as main canal, branch canal,
distributary canal etc into the natural drain.
1101- Due to reasons for surplus amount of water to be present in the canal,
the supplies shall be reduced or stopped from the head works. Therefore in
order to avoid this damage immediate action is needed. This can be achieved
by the means of an escape generally called surplus water escape.

22- Ground Water through Wells and Tube wells – Infiltration:

1102- Infiltrometer is used for field measurement of infiltration. There are
two types of infiltrometer – Single ring infiltrometer and Double ring
infiltrometer. Single ring infiltrometer always overestimate because of the
lateral movement of water and to overcome this double-ring infiltrometer is
used.
1103- Rainfall simulators are used for laboratory measurement of infiltration
and Infiltrometer is used for field measurement of infiltration. Lysimeter is
used to measure evapotranspiration and tensiometer is used to measure
capillary potential.
1104- The rate of infiltration is directly proportional to the temperature. As
temperature increases, viscosity decreases and resistance to flow decreases
and infiltration increases.
1105- Soils having small pore size such as clay have low infiltration capacity
than the soils having large pore size such as sandy soil. One exception is when
the clay is present in dry conditions; the soil can develop large cracks which
lead to higher infiltration capacity.
1106- The rate of infiltration measured by infiltrometer is more than the
infiltration rate determined by the rainfall simulator. The rate of infiltration is

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directly proportional to the depth of surface retention. As the depth of
retention is more in infiltrometer hence the rate of infiltration is more in
infiltrometer.
1107- Infiltration is the process by which the water seeps into the surface
strata of the earth to meet soil moisture deficiencies. Percolation is the deep
vertical movement of water in the ground.
1108- Grass cover or vegetation cover increases the field capacity by trapping
water and reducing the effect of raindrop compaction. Vegetation and grass
cover also reduces the surface compaction of the soil which again allows for
increased infiltration.

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23- Aquifers and Their Type:
1109- The geological formations which are porous and contain a good
amount of water but does not yield water freely to wells due to its lesser
permeability is called aquitard. The water yield from such a formation is
insignificant. Sandy clay is an example of the aquitard.
1110- The geological formations which are porous but have no permeability
are termed as an aquiclude. Water cannot be extracted from such formations.
A clay layer is an example of aquiclude.
1111- The geological formations which are both porous and permeable hence
sufficient quantity of water can be extracted from them. Aquifers vary in
depth and thickness and in general, confined and non-confined aquifers are
two main categories of the aquifer.
1112- The geological formations which are very dense and contain no water
in voids and are neither porous nor permeable are termed as aquifuge.
Granite rock is an example of aquifuge.
1113- When the saturated formations are drained under the action of gravity
drainage, the volume of water drained is less than the volume of void space.
The water contained in these voids cannot be drained out by force of gravity.
The water which is always retained by these interstices due to molecular
attraction is called pellicular water.
1114- The gravity wells which are constructed to tap water from the
unconfined aquifer are known as unconfined or non-artesian wells. Such wells
are also known as water table wells or gravity wells since the water level in
these wells is equal to the level of the water table.
1115- Perched water table is the top surface of the water held in the perched
aquifer. Cone of depression is the surface of the water table surrounding the
well which takes up a curved shape. The piezometric surface is an imaginary
surface that defines the level to which water will rise representing the total
head in an aquifer.
1116- The permeability is inversely proportional to the viscosity of water and
viscosity decreases with increase in temperature. Hence, permeability will
increase with an increase in temperature.
1117- Specific capacity of a well can be defined as the well-yield per unit of
drawdown. The value is not constant but decreases as the discharge

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increases. The value is not the same for all drawdowns, it should be
determined for the fall of the first meter.
1118- The specific yield is expressed as the ratio of the volume of the water
obtained by gravity drainage to the total volume of the material drained.
Since, Specific yield + Specific retention = Porosity. Evidently, the specific yield
is less than the porosity.
1119- The following equation shows that specific capacity decreases as Q
increases and Q increase only when the drawdown is increased by heavier
pumping and hence, specific capacity decreases as drawdown is increased.
Specific capacity = Q/ (C1.Q + C2.Q2). i.e. Discharge/ Drawdown (Well loss +
Aquifer loss).
1120- Unconfined aquifer is the one in which the topmost water-bearing
stratum having no confined impermeable overburden lying over it. Aquifer
water serves as an upper zone of saturation and it is subjected to hydrostatic
pressure only.

24- Tube Well and Dug Well:

1121- The velocity of the percolating water depends on the depression head. If the
amount of water withdrawn from the well is more, increasing the depression head,
higher flow velocities will prevail in the vicinity of the well. At a certain stage,
depression head may become so great that the soil particles also start coming with
the percolating water.
1122- Specific capacity is the measure of the well performance indicating the rate
of water percolation into a well. It is also defined as the yield of a well under the
head of one meter. The specific capacity of the well is not constant but decreases
as the discharge increases.
1123- Yield of a well is the rate at which water percolates into the well under the
safe maximum depression head or the critical depression head. It depends on the
position of the water table, permeability, and porosity of the soil, rate of water
withdrawal from the well, and amount of water storage in the well.
1124- Jet pumps have low efficiency of the order of 35% as compared to 65-85%
for other centrifugal pumps. It is not used for irrigation tube-wells.

25- Gravity Dams:

1125- An opening or passage left in the dam which runs longitudinally is called
the gallery. This is to provide space for drainage of water percolating through
the upstream face of the dam or seeping through the foundation. It is also
used for inspection purposes and for the mechanical equipment used in the
operation of gates in spillways.

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1126- In a gravity dam, the grout curtain is provided near the toe to reduce
the exit gradient. A drainage gallery with its drainage pipe system provided in
gravity dam reduces the uplift pressure at all levels below the upstream water
level. Vertical cut-off walls are the most effective to reduce seepage flow and
uplift force.
1127- Transverse joints are vertical joints that run through the entire height
and extend through the full width of the dam section. These joints are
continuous from the upstream face to the downstream face.
1128- Water bars or water stops are provided in the transverse as well as
horizontal joints in concrete adjacent to the upstream face of the dam. The
openings of the joints are sealed properly with water stops to avoid passage
of seepage of water through the body.
1129- Curtain grouting helps in forming a principal barrier against the
seepage through the foundations and thus reduces the uplift pressure. This
grouting can be accomplished from the foundation gallery or from other
galleries within the dam.
1130- The concrete is poured from a certain height in the first attempt and
this height is called a lift. Maximum height of single pour of concrete is usually
about 1.5 m. If this is reduced, more horizontal joints will get developed.
1131- Transverse joints are vertical joints that divide the dam length into a
number of vertical cantilevers each of which is independent of the other. It
runs through the entire height and extends through the full width of the dam
section. Hence, it justifies the two-dimensional analysis of gravity dams.
1132- The waves developed near the top surface due to the winds notch out
the soil from the U/s face and the D/s toe of the dam may get eroded due to
the cross currents and due to tail water. Stone pitching or riprap should be
provided to avoid such failures.
1133- The rainwater that acquires high downward velocities causes
consequent erosion which can be reduced by the provision of berms.
The provision of berms serves the following purposes –
• It behaves like a good lining for reducing losses and leakage
• They provide protection against erosion and breaches due to wave action
• They help the channel to attain regime conditions as they help in providing
a wider waterway
• It can be used as borrow pits for excavating soil to be used for filling.

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1134- When the upstream slope is steep and when the soil used in the
construction of the dam is poor and compaction is not adequate, the sudden
drawdown of water causes sliding of the upstream face. This failure seldom
leads to catastrophic failures.

c) Renewable Energy:
1- Classification of Energy Resources:
1135- On the basis of usability, Energy Resources are classified into Primary,
Intermediate and Secondary Resources. Primary Resources are present in
nature prior to human interference or modification. Intermediate Resources
are obtained from primary resources after one or more stages of
transformation while Secondary Resources are the form of energy that is
finally supplied to the consumer for utilization.
1136- On the basis of usability, Energy Resources are classified into Primary,
Intermediate and Secondary Resources. Primary Resources are present in
nature prior to human interference or modification. Intermediate Resources
are obtained from primary resources after one or more stages of
transformation while Secondary Resources are the form of energy that is
finally supplied to the consumer for utilization.
1137- Conventional sources of energy are those sources that are being used
traditionally for a long time i.e. coal, petroleum, firewood, etc. Non-
conventional sources are relatively new in terms of utilization.
1138- Solar energy is a source of energy that has not been used traditionally
and is relatively new in terms of usage. Hence it is a non-conventional source
of energy. It is unlimited and inexhaustible and hence is a renewable source
of energy.
1139- Wind energy is directly available in the environment, so it is a primary
energy source while Hydrogen energy is obtained from fossil fuels and hence
is a secondary energy source.
1140- On the basis of traditional use resources are classified into
conventional and non-conventional resources. On the basis of long-term
availability, resources are classified into renewable and non-renewable
resources. Based on the usability of energy, resources are classified into
primary, intermediate and secondary resources. Based on commercial

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applications, resources are classified into commercial and non-commercial
resources.

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1141- Coal and gasoline are commercial resources that are widely used in
industries such as Steel, Cement, Electricity, etc. Firewood and crop residue
are generally used for domestic purposes. Biogas has some industrial uses
such as for electricity generation but is not used widely.
1142- Coal, Methane, and Biogas produce CO2 during electricity generation
as all of them have some carbon content, which on combustion produces CO2.
Uranium produces energy by the process of nuclear fission and does not
produce CO2.
1143- Based on Origin, energy resources are classified into Fossil fuels,
Nuclear, Solar, Wind, Biomass, Geothermal, Tidal, Ocean thermal, Ocean
wave and Hydro energy.
1144- 89 percent of the total energy produced is from non-renewable
resources i.e. Coal (27%), Natural Gas (24%), Oil (34%) and Nuclear Energy
(11%). Only 11% of the world’s energy needs are fulfilled by Renewable
resources.

2- Importance of Non-Conventional Energy Sources:

1145- The increasing world population has caused the world energy needs to
rise significantly. Apart from the rapid growth of industries, the formation of
new ones has increased the energy needs of the world. Due to these reasons,
Conventional sources of energy are not enough, and hence we need
alternative energy sources.
1146- Conventional energy sources like Coal, Petroleum, Natural gas, etc., are
major causes of pollution and ozone layer depletion. There are limited
reserves of conventional energy sources, which are bound to be finished. At
the current rate of consumption, the approximate lifetime of the world’s
petroleum, natural gas, and coal reserves are 50 years, 52.8 years, and 153
years, respectively. Oil is the most used energy source in the world. At present
31 percent of the world energy needs are fulfilled by Oil.
1147- Solar pond collects thermal energy from sunlight. The salt content of
the pond increases with depth. It doesn’t require any fuel for storing energy.
Apart from fulfilling energy needs, fossil fuels are also used as feedstock
materials for the manufacture of organic chemicals. Solar dryers are used to
dry foods i.e. Fruits, Vegetables, etc. In Hydroelectric power plants, turbines
are rotated by the Kinetic Energy of water.

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3- Environmental Aspects of Energy:

1148- Anthropogenic greenhouse gas emissions is accused of causing global
warming especially due to the expansion of industries since the past 150
years. Sulphur and aerosol emissions cool the planet.
1149- Burning fossil fuels for various industrial and domestic processes since
the past 100-150 years has led to global warming. Releasing CFCs into the
atmosphere damages the ozone layer.
1150- The major problems with wind energy is that it requires large area of
land. It also poses a threat to wildlife habitat like destruction of birds. It is a
renewable source of energy because it generates energy from wind.
1151- Acid rain is basically rainwater which is acidic. It is caused by dissolution
of harmful gases like sulphur dioxide and carbon monoxide in clouds during
precipitation thereby polluting the clean rainwater.
1152- Acid rain is acidic. Any acid has a pH value less than 7. So, the pH level
of acid rain lies between 3-4. Practically, substances with pH values lying
between 6-8 are considered neutral.
1153- Ozone protects the earth and its creatures from the harmful UV
radiations. These radiations are known to damage the eye and cause many
skin diseases.
1154- Aerosols, CFCs and freons damage the ozone layer. They react with
ozone molecules and reduce the amount of ozone molecules in the
stratosphere. This lets harmful UV radiation into earth.
1155- IPCC stands for “Intergovernmental Panel on Climate Change”. It is an
intergovernmental body of UN that provides scientific information regarding
climate change and its effects. It is non-profit organization.

4- Environment-Economy-Energy and Sustainable Development:

1156- “3E” is a nomenclature used for energy, economy and environment. It
describes the interrelation between them. “3Rs” are used for reduce, reuse
and recycle.
1157- Sustainable development requires that energy resource cannot be
exhausted completely. If anyone resource is at the brink of exhaustion, it has
to be substituted by another or a shift to another source has to be made.

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1158- Sustainable consumption and production aims to reduce resource
consumption. It also aims to reduce waste generation and emissions across
the full life cycle of processes and products.
1159- A green economy is a low carbon, resource efficient and socially
inclusive economy. Without the society being consciously involved, the green
economy cannot be created let alone sustain.
1160- Sustainability can be achieved by replacing existing resources with
other resources of equal value or of greater value. However, it should be
noted that the replacement or operation of these new resources does not
degrade the environment.

5- World Energy Status:

1161- Solar energy, especially photovoltaic are becoming popular low-carbon
energy sources. Photovoltaic systems are installed in both, industries and
houses to meet their respective energy demands.
1162- Transportation energy is projected to increase by 40% between 2018
and 2050. The increase is largely driven by growing energy demands in
developing countries.
1163- Energy policy is basically a methodology formed by an entity (usually
governments) to address issues related to energy development. This includes
energy production, distribution and consumption.

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1164- The main aim of implementing an eco-energy-oriented policy is to
tackle global warming and climate change. The idea is to manage energy
production, distribution and consumption without damaging the
environment.
1165- Renewable energy has the potential to mitigate climate change. This is
because it has a low carbon footprint and is specifically used to prevent
further damage to the environment.

6- Sun, Earth Radiation Spectrums:

1166- Solar radiation is the energy radiated from sun in all directions. Energy
radiated from earth is not solar radiation. Any random radiation traveling in
space is called cosmic rays.
1167- The three relevant bands of solar radiation are ultraviolet (UV), infrared
and visible bands. Far infrared and near infrared are components of infrared.
Ultrasonic is related to sound waves.
1168- Infrared and UV are the major components of the total solar radiation
reaching earth. Infrared radiation makes up 49.4% and visible light makes up
42.3%. Only 8% of the total radiation is in the UV band.
1169- Direct solar radiation is solar radiation directly received by earth’s
surface from sun. It is called direct because no scattering or reflection occurs.
Cosmic radiation is not same solar radiation.
1170- Earth emits infrared radiation. This is typically called as outgoing long-
wave radiation (OLR) of wavelength between 3 and 100um. They are also
called as thermal radiation.
1171- Infrared radiation is responsible for thermal and heat energy. They lie
on the opposite side of the spectrum from ultraviolet light. This radiation has
a wavelength greater than 700nm.
1172- Infrared radiation cause heat by exciting electrons. When they are
absorbed by substances, they interact and excite electrons by transferring
energy. This leads to heat as the atom (or electron) is said to be in excited
state.
1173- Photosynthetically active radiation (PAR) is the radiation best suited for
photosynthesis. It is basically wavelength range in which photosynthesis
occurs with ease. This range is between 400nm and 700nm – visible range.

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1174- The flux of energy transported by outgoing long-wave radiation is
measured in watt/square meter. While Watt is used to measure power, Joule
is used to measure energy.
1175- In earth’s climate system, the processes involved in long-wave
radiation are absorption, scattering and emissions. The emissions are from
atmospheric gases, aerosols, clouds and the surface. Condensation is the
process of gas converting to liquid due to decrease in temperature.
1176- Sun is the source of energy for all living organisms on earth. It provides
energy for photosynthesis which triggers the biological food cycle and food
web. Thus, the energy is transferred between organisms as described in the
biological energy pyramid.
1177- Earth’s energy budget is the balance between received energy and
emitted energy after the distribution of energy throughout the five
components of earth’s climate system. It is important to note the outgoing
energy is the energy after distribution.
1178- When the incoming energy is greater than the outgoing energy, the
earth’s temperature rises. This results in global heating and the entire planet
feels the “heat”.
1179- When the incoming energy is lesser than the outgoing energy, the
earth’s temperature decreases. This results in global cooling. If the difference
is large and average global temperature decreases even by 1 degree Celsius,
the entire planet may be covered with snow.
1180- Solar irradiance is the intensity with which the solar radiation enters
the earth’s atmosphere. Solar radiation directly received by earth’s surface is
called direct solar radiation. Solar radiation received by earth’s surface after
scattering is called indirect solar radiation.
1181- Earth’s temperature is nearly stable. This is because the incoming
short-wave solar radiation nearly equals the outgoing long-wave radiation.
Any variation in the global average temperature is detrimental to the planet.
1182- Intensity is best described by the brightness of a glowing bulb. Energy
the bulb radiates as heat is the power that is wasted by the bulb during its
operation.
1183- Solar irradiance is measured in watts/square meter. It is the amount of
radiant flux on an area and hence those units. Speed and velocity are
measured in meters/s.

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1184- Ozone absorbs UV light and hence affects solar irradiance. The lower
the angle of the sun, the larger the amount of ozone the light has to pass
through.
1185- The distance that the solar radiation has to travel will be lowest when
the sun is directly overhead. The angle of sun is dependent on latitude, time
of year and the time of day.

7- Measurements of Solar Radiation:

1186- The two basic ways to measure solar radiation are via ground-based
instruments and satellite measurements. Anemometer is an instrument used
to measure wind speed. Voltmeter is an instrument used to measure
potential difference between two points conducting electric (DC) current.
Ammeter is an instrument used to measure the electric (DC) current flowing
across two points.
1187- Actinometer is used to measure the intensity of an incident radiation.
Wind speed and wind direction are measured by anemometer and wind vane
respectively.
1188- A pyranometer belongs to the category of actinometer because it is
used for measuring solar irradiance. Voltmeters are used to measure
potential difference between two electrically conducting points. Hall sensors
are used to measure current via magnetic fields. Amplifiers are used to
“amplify” currents or voltages.
1189- Global and diffuse solar radiation can be measured by thermoelectric
pyranometers. Heat pumps are used in thermal systems to pump heat from a
cooler region to a hotter region. Oscilloscopes are used to observe sinusoidal
outputs.

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1190- Generally, a pyrheliometer is used to measure direct solar radiation.
Actinometer are a class of devices/systems that measure intensity of
radiation. IC tester is used to test ICs.
1191- Photodiode is a physical device that can be correlated to the number
of photons detected. LEDs and CFLs are devices that emit light (radiation).
CFCs are a type of gas that harm the ozone layer.
1192- The main difference pyranometer and pyrheliometer is the purpose of
measurement. Pyranometer is used to measure global solar radiation and
hence it is used for both visible and UV. Pyrheliometer is used to measure
direct solar radiation.

8- Solar Collectors:
1193- A solar collector is a system to collect heat by absorbing sunlight and
use it for various applications. It is neither a system to collect rainwater nor
electricity. However, it could be used to perform such processes.
1194- Aperture area of a receiver is that area which receives the solar
radiation. It need not be same as the entire size of the receiver. It is not same
as the area occupied by the system after installation.
1195- A flat plate solar collector consists of various components. Firstly, it
consists of a flat box or an enclosure to hold the entire setup. A dark coloured
plate is fitted with fluid circulation passageways and transparent cover.
Finally, a circulating fluid which flows through the entire setup.
1196- A transparent cover is used in a flat plate collector. This is because it
maximizes the transmission of the incident sunlight into the box thereby
collecting maximum sunlight for thermal energy.
1197- Water is used as circulating fluid in tropical and sub-tropical climates.
This is because it has good properties as a coolant. A mixture of water with
ethylene glycol or glycerol or propylene glycol is not used as coolant in
tropical and sub-tropical climates.
1198- Overheating is a common problem with evacuated-tube solar collector.
This is because of the high temperatures of the circulating fluid caused by
collection of large amount of sunlight.
1199- Solar water heater is a system that converts sunlight into heat. This
heat is then used to heat water. As the water gets heated, steam may be

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produced but the purpose of solar water is to heat water and not produce
steam. It does not generate current.

9- Origin of Winds:
1200- The energy that drives winds originates from the sun’s heat received
along with sunlight. The heat creates areas of low pressure and high pressure,
thereby causing winds to blow. Wind is abiotic and does not need food. Any
wind blowing due to man is artificial. Water aids in magnifying a low or high
pressure area but does not cause winds.
1201- Wind always flows from a high pressure area to a low pressure area.
The difference in pressures causes wind to flow from in a direction. Winds
originate from the heat received by sun which heat’s the earth’s surface
unevenly resulting in a pressure difference.

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1202- The direction of wind is generally indicated by weather vanes,
windsocks and balloons. Multimeters and oscilloscopes are electronic
instruments used to measure voltage and current. Accelerometer is a device
that measures a body’s acceleration.
1203- Eddies are small areas where the local wind blows opposite to that of
the net direction of wind-motion for a short period of time. Eddies are always
local in nature and do not occur globally.
1204- Anemometers are used to measure wind speeds. They are commonly
used in weather stations. Odometers measure distance of a wheeled vehicle.
Ammeters measure current and weather vanes are used to indicate the
direction of wind.
1205- A wind turbine can be located anywhere in a good wind site provided
the rotor is installed slightly on a higher terrain. The rotor is typically mounted
30 feet above the tallest obstacle within a 500-foot radius.
1206- Before selecting and deciding on a good site, various impacts of
installing a wind turbine are considered. The engineers ensure that the wind
site does not harm any living creature. They also ensure that the site is far
away from the nearest village to prevent any noise pollution.
10- Wind Turbine Types and their Construction:
1207- Wind turbines convert wind energy to mechanical energy. This
mechanical energy is then converted to electrical energy using an electric
generator. They neither convert wind energy to heat energy nor to solar
energy.
1208- A wind turbine system first converts wind energy to mechanical energy
and then to electrical energy using an electric generator. The correct order is
blades – rotor – shaft – electric generator.
1209- Rotor blades are made using glass fiber reinforced polyester (GRP). It is
a material made impregnating a matrix of fiber glass mats with a polyester.
This polyester is hardened after impregnation.
1210- Tower, nacelle, rotor and blades, power converter, electricity
generator and wind shaft are the major parts of a wind turbine system. Water
storage tank, air compressor and vacuum pump are not used in a wind turbine
system.

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1211- The main function of tower in a wind turbine system is to support the
other components. It also stabilizes both, the rotor and blades which
eventually convert wind energy to electrical energy via mechanical energy.
1212- The blades rotate slowly and this speed is not sufficient to generate
electricity. So, the main function of a gearbox in a wind turbine system is to
multiply the rotation speed to a sufficiently high level so as to generate
electricity.
1213- A pitch drive motor is a motor used to control the angle of blades.
Pitching is the process of rotating the angle of blades to cut maximum wind
for harvesting energy.

11- Wind Energy Conversion Systems (WECS):

1214- Wind energy conversion systems (WECS) are designed to convert wind
energy to mechanical energy. The kinetic energy of the wind is used to turn
the blades of a wind turbine which in turn rotates a rotor connected to it. This
mechanical energy is further converted to electrical energy for various
applications.
1215- Wind turbine is a crucial part of a wind energy conversion system
(WECS). It converts the kinetic energy of the incoming air stream into
mechanical energy which is then converted to electrical energy. Server, cloud
user and service provider are components of a wireless communication
system.
1216- Parallel shaft and planetary gearboxes are used in wind turbine.
Differential and manual transmission are used in automobiles. VAWT and
HAWT are the two most commonly used wind turbines.
1217- When the input and output shaft of a gearbox are aligned, it is called
planetary gearbox. It is used to transfer the largest torque compactly. Motor
shaft and speed controller shaft in parallel shaft.
1218- Parallel shaft gearbox is used in small turbines. They have a simple
design and are easy to maintain. Also, they are made up high mass material.
1219- Power generation contains electromagnetic and electrical subsystems.
To ensure voltage compatibility with grid, it generally contains an electrical
transformer apart from the electrical generator and power electronics
converter.

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1220- The function of rotor side converter is to control the generator. It
controls the generator in terms of active and reactive power by ensuring
minimum power loss during power conversion. The rotor side converter is
made up of IGBT.

12- Wind Energy Storage:

1221- Most of the electricity produced from the plants is consumed
immediately. Moreover, wind power generation is not correlated to the
demand cycle. It is also not guaranteed to be available during peak demands.
Thus, wind power storage is necessary.
1222- Wind energy can be stored as electro-chemical energy in the form of
batteries. Glowing a bulb and running a consumer electrical appliance
consumes energy. While turning off an appliance when not in use saves
energy, it doesn’t store energy.
1223- Electro-hydrogen is an example of storing wind energy chemically.
Batteries typically come under the category of electro-chemical storage.
Flywheels come under the category of mechanical storage.
1224- Wind energy cannot be switched on ‘on demand’. It is inherently
intermitted, variable and non-dispatchable. To match the supply with
demand, it requires a backup to store the generated power.
1225- Energy storage capacity is the amount of energy a storage device can
store for a period of time. It is usually measured in kilowatt-hours (KWh) or
megawatt-hours (MWh). It is not the same as amount of energy stored.
1226- Phase change materials are used for latent heat storage. Stress and
strain are used to describe a material’s deformation ability. Elastic materials
are those which when deformed regain their original shape.

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1227- Flywheels are an example of storing mechanical energy in the form of
kinetic energy. The flywheel (or rotor) is accelerated to a high speed thus
maintaining the energy. The energy is stored in the system in the form of
rotational kinetic energy.
1228- Capacitors store energy in the form of electric potential. The energy is
stored between two metallic plates. Neither AC voltage nor alternating
current can be stored.
1229- PHES uses the gravitational potential energy of water to generate
electricity. During off-peak hours, water is pumped from a reservoir at a lower
level to a reservoir at a higher level and stored. When required, the water falls
from the higher level and rotates turbines connected to an electrical
generator.
1230- A flywheel energy storage (FES) consists of a central shaft. The shaft
holds a rotor and a flywheel. The central shaft rotates on two magnetic
bearings which considerably reduces friction losses. The entire setup is placed
in vacuum to prevent drag losses.
1231- The entire setup is mechanical, it can be repeatedly charged and
discharged without much damage to the setup itself. Thus, flywheels are used
in uninterrupted power supplies (UPS).

13- Solar Radiation on Inclined Plane Surface:

1232- Net power received from incident sunlight depends on two things – the
power contained in the sunlight and the angle of the receiver with respect to
the incident sunlight. Incident power equals the received power when the
receiver is perpendicular to the incident sunlight.
1233- For a fixed receiver, incident power density and received power
density are not equal always. In fact, the net received power is often less than
the incident power as the angle between the sun and the receiver changes
continuously.
1234- Diffused solar radiation is that radiation which has been scattered by
molecules and particles in atmosphere. Though it deviates from its initial
path, it does travel down to the earth.
1235- Receivers are tilted to maximize the collection of direct solar radiation
from the sun. The tilt tries to ensure that the receivers are perpendicular to

167
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the direct radiation. It accounts for the continuous change in angle between
the sun and the receiver.
1236- When solar receivers (panels) are laid horizontally, they usually collect
diffused radiation. This is because diffused radiation is equally distributed
throughout the sky and hence can easily be gathered.
1237- Global insolation or total insolation is the sum of the radiation received
by earth from sun. It is nothing but the sum of direct radiation, diffused
radiation and reflected radiation. This is used as a reference for the insolation
at some tilt.
1238- Hour angle of sun is defined as the actual orientation of earth with
respect to the sun. Mathematically, it is calculated by converting earth’s one
rotation in degrees and dividing it by the time taken – 360/24 = 15 degrees/h.

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1239- Solar intensity is defined as the amount of incoming solar energy on a
plane surface per unit time per unit area. It is a weighted average of the full
radiation and is equal to 1367 Watt/square meter.
1240- Solar azimuth angle is defined as the angular distance between zero
azimuth and the projection of the line of sight to sun on the ground. Zero
azimuth is a line due north or due south. Azimuth angle is measured clockwise
from zero azimuth.

14- Photosynthesis Process:

1241- Photosynthesis is the process by which photoautotrophs generate food
for themselves. They use carbon dioxide, water and sunlight to generate
carbohydrates and oxygen. Photo means light.
1242- The primary product of photosynthesis is glucose. Oxygen is the by
product. Water and carbon dioxide are the reactants.
1243- Photosynthesis occurs in the presence of sunlight. The balanced
reaction of photosynthesis best describes the process of photosynthesis. The
option with oxygen and glucose as reactants is not photosynthesis.
1244- Conversion of usable sunlight energy into chemical energy is associated
with green pigmentation. This green pigmentation is called chlorophyll. Plants
and algae consist of chlorophyll which is a key ingredient for photosynthesis.
1245- Condensation reaction is responsible for splitting out water molecules
and phosphorylation. Phosphorylation is the addition of a phosphate group
to an organic compound. Electron transfer occurs in a redox reaction.
1246- Electrons of chlorophyll molecule gain energy and move to higher
energy level when light is absorbed. On gaining sufficiently high energy, the
electron leaves the molecule thereby forming a positively charged chlorophyll
ion. This process is called photoionization.

15- Usable Forms of Biomass, their Composition and Fuel

Properties:
1247- Biomass is a term for all organic materials stemming from living
organisms like plants, animals and microorganisms. Examples of biomass are
– animal waste, dead plants and animals, sugar, fats, etc.
1248- Agricultural residue is an example of cellulosic biomass. They generally
include leftover material from crops like stalks and leaves. Fats, lipids and
glucose are not cellulosic biomass.

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1249- Biomass can be converted to electrical and heat energy. It can also be
used as transport fuel and chemical feedstock. It cannot be converted to light
energy.
1250- The heating value is expressed in BTU/kg. BTU stands for British
Thermal Unit and is used to measure thermal (heat) energy. It is the amount
of energy needed to raise 1 pound of water 1 degree farad at sea level. Other
commonly used units are MJ/kg and cal/g.
1251- Heating value indicates the total amount of energy that is available in
the fuel. It is one of the most important characteristics of a fuel. It is mostly a
function of fuel’s chemical composition.

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1252- Higher heating value is the total amount of energy available in the fuel,
including energy contained in water vapor in the exhaust gases. Heating value
indicates the total amount of energy available in the fuel.
1253- Lower heating value (LHV) is total amount of energy available in the
fuel – energy contained in water vapor in the exhaust gases. Generally, LHV is
not an appropriate value to use for biomass combustion.
1254- High moisture content in fuels do not allow them to burn readily and
provide less useful heat per unit mass. This is because water itself does not
provide any energy value. In fact, much of the supplied energy is used to heat
and vaporize water which leads wastage of supplied energy.
1255- Biomass is seasonal, especially plant biomass. This is a problem
because most biomass comes from agricultural feedstock. However, the
energy and feedstock demands are continuous irrespective of season.
1256- Burning biomass does not add to greenhouse gas emissions because it
does not release any additional amount. Instead, it released the same amount
of gas that was captured and converted to other forms during its growth.
1257- Intrinsic moisture content is the moisture content in biomass without
the influence of weather effects. It does not depend on the amount of
moisture content present in the atmosphere.
1258- High moisture content or an increase in moisture content is a problem
for biomass combustion. This is because, the amount of energy that can be
used for applications is significantly reduced due to absorption of moisture.
The heat used to burn the fuel will first be used to evaporate the water vapor
thereby leading to excess use of resources.
1259- Calorific value is another important property that indicates how good
the biomass is. It is the amount of energy content or heat value released by
the material when burnt in air. Burning or combustion is usually not done in
water.
1260- Volatile matter is that content in biomass which is driven off as gad by
heating. It also includes the water vapor. Moisture content present in biomass
is not volatile matter by itself. When it turns into water vapor, it can be called
as volatile matter.
1261- Fixed carbon content is the mass that remains after the releases of
volatile matter on heating the biomass. Since it is fixed and not released as
gas, it is called fixed carbon content.

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1262- The chemical breakdown either by thermo-chemical or bio-chemical
processes of biomass produces a solid residue. When the residue is produced
by combustion in air, it is called ash.
1263- Land fill is an example of wet waste. It consists of residential wastes,
industrial wastes and other wastes from sewage. It also consists of manure in
the form of animal wastes.
1264- Many industrial wastes are used as methane boosters due to their
extremely high methane potential. Agricultural, municipal and forestry
wastes are not suitable for methane boosters.

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1265- Aquatic biomass in the form of micro-organisms are used for waste
water treatment. They operate in anaerobic environment during the
treatment.
1266- Carbon to nitrogen (C: N) ratio is one of the most important parameters
used to talk about the sustainability of the biogas feedback. Heating and
calorific value are parameters to describe the available fuel in a given
biomass.

16- Biomass Conversion Technologies:

1267- The three main technologies used to convert biomass into useful forms
of energy are bio-chemical, thermo-chemical and physio-chemical processes.
Galvanization is a process used to prevent corrosion of metals. Doping and
photoelectric effect are not related to biomass conversion technologies.
1268- The four main types of thermo-chemical processes are pyrolysis,
gasification, combustion and hydrothermal processing. Photovoltaic effect,
doping, chemo-mechanical effect and galvanization are not related to
biomass conversion technologies.
1269- Anaerobic digestion and fermentation are two primary processes
under bio-chemical conversion. Photosynthesis, photovoltaic and respiration
are not related to biomass conversion technologies.
1270- Physio-chemical process mainly consists of extraction with
esterification. Pyrolysis and gasification are thermo-chemical conversion.
Anaerobic digestion is a bio-chemical conversion process.
1271- In pyrolysis, the biomass is subjected to high temperatures in the
absence of oxygen. The output of pyrolysis is producer gas which is a mixture
of flammable gases (primarily CO and H2) and non-flammable gases (primarily
nitrogen and carbon dioxide).
1272- Gasification basically converts all the available biomass to “gas”. In the
first stage, the biomass is partially combusted to form producer gas and
charcoal which is then sent to the second stage. In the second stage, the
carbon dioxide and water produced in the first stage is chemically reduced by
charcoal to form carbon monoxide and hydrogen.
1273- Hydrothermal processing is a biomass conversion technique that
involves heating of aqueous slurries of biomass at high pressures to produce

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products of greater energy density. Feedstocks with high moisture content
like manures are best suited for this process.
1274- Anaerobic digestion is a biological process of breaking down the
biomass to produce products with high energy density – biogas. It occurs in
anaerobic conditions. Waste water treatment plants commonly use
anaerobic conditions to treat the influent.
1275- Catalytic liquefaction is a thermo-chemical biomass conversion
process. It requires low temperature and high pressure and the process is
carried out in liquid phase under the presence of a catalyst.
1276- Yeast is commonly used in fermentation process. Fermentation is the
process converting biomass to alcohol and carbon dioxide.
1277- Fermentation is an anaerobic process. It is another commonly used bio-
chemical process of converting feedstock (biomass) to energy in the presence
of micro-organisms.

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1278- The two main products of anaerobic digestion are biogas and bio-
fertilizer. Wastewater is the input to the anaerobic digester. Producer gas is
produced during pyrolysis.
1279- Methane gas and carbon dioxide are present in biogas. Butane is not
present in biogas. Nitrogen and sodium are not organic compounds.
1280- Nitrogen, hydrogen and carbon monoxide are the contaminant gases
present in biogas. Methane gas and carbon dioxide constitute the fuel present
in biogas. Chlorine and fluorine are not present in biogas.
1281- Thermo-chemical processes do have higher efficiencies than bio-
chemical processes. In fact, they also have quicker reaction times and
superior ability to decompose most organic compounds.
1282- Thermo-chemical conversion techniques can decompose lignin. When
compared with bio-chemical conversion techniques, they have superior
ability to decompose most organic compounds. Anaerobic digestion and
fermentation are bio-chemical processes.
1283- Hydrothermal liquefaction produces bio-crude which can be distillated
to obtain petroleum products. Bio-oil is produced in fast pyrolysis. Producer
gas is produced in pyrolysis and syngas is produced in hydrothermal
gasification.

d) - Fluid Mechanics:
1- Introduction to Fluid Mechanics:
1284- A fluid is a Tresca material with zero cohesion. In simple words, fluid is
in a state of failure.
1285- Solid molecules have a definite shape due to large inter-molecular
forces. In liquids, molecules are free to move inside the whole mass but rarely
escape from itself. Thus, liquids can form free surfaces under the effect of
gravity. But, in case of gases, molecules tend to escape due to low forces of
attraction. Thus, gases won’t form any free surface.
1286- Fluid Mechanics deals with the study of fluid at rest or in motion with
or without the consideration of forces, Fluid Statics is the study of fluid at rest,
Fluid Kinematics is the study of fluid in motion without consideration of forces
and Fluid Dynamics is the study of fluid in motion considering the application
forces.

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1287- Ideal fluids are incompressible which means they will have zero
compressibility.
1288- Ideal fluids are non-viscous which means they will have zero viscosity.
1289- Ideal fluids has zero surface tension but real fluids have some finite
value of surface tension.
1290- Mass Density (p) is defined as the mass (m) per unit volume (V), i.e., p
= m ⁄v
Thus, the unit of p is kg = m3.
1291- The specific gravity of a liquid is the ratio of two similar quantities
(densities) which makes it unitless
1292- Specific weight (γ) is defined as the weight (w) per unit volume (V),
i.e.,
γ=w/v
Thus, unit of is N = m3..
1293- Mass Density (p) is defined as the mass (m) per unit volume (V), i.e.,
[p] = [m]/[v] = [m] /[L3] = [ML-3].
1294- Specific volume (v) is defined as the volume (V) per unit mass (m).
Thus,
[v] = [V]/[m] = [L3]/[M] = [M-1L3].
1295- Specific weight(γ) is defined as the weight(w) per unit volume(V ), i.e.,

2- Fluid Properties:
1296- Mass Density (p) is defined as the mass (m) per unit volume (V), i.e., p
= m ⁄v
3
Thus, the unit of p is kg = m .
1297- For an incompressible fluid, the change in density is negligible. Thus it
does not change with temperature and pressure.
1298- Specific weight is inversely proportional to volume. For incompressible
fluid, variation of volume with temperature and pressure is negligible for
practical consideration. Therefore, specific weight remains constant.
1299- Specific gravity is characteristic property of fluid and is independent of
external conditions.

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1300- Viscosity is the internal friction of a fluid in motion. It is the property by
the virtue of which the relative motion between two adjacent fluid layers is
opposed.
1301- Viscosity is the property of a fluid and is constant for a given fluid under
given conditions, irrespective of the fact whether the fluid is at rest or in
motion.
1302- Viscosity of a liquid is due to the cohesion between its molecules. With
the increase in temperature of a liquid, cohesion increases, leading to the rise
in viscosity. Viscosity of a gas is due to the momentum transfer between its
molecules. With the increase in the temperature of a liquid, molecular motion
increases, leading to the fall in viscosity.

1303- Explanation:
where F= viscous force, A= area, du ⁄ dx = velocity gradient, μ = co-effcient of
viscosity. Therefore,

SI unit of μ is N-s/m2 = Pa-s and CGS unit of μ is dyne-s/cm2. 1 Poise= 1 dyne-

s/cm2 and 1 Stokes= 1 cm2/s. Thus, Stokes is not a unit of μ, rather it is a unit of
kinematic viscosity υ.

1304- Where F= viscous force, A= area, du ⁄ dx = velocity gradient, μ = co-

efficient of viscosity. Therefore,

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1305- ν = μ/ρ, where ν = kinematic viscosity, μ = dynamic viscosity and ρ =
density of the fluid.

1306- It is the characteristic property of gases which show increase in

viscosity with increase in temperature.
1307- In case of incompressible fluids, cohesive forces govern the viscosity.
As temperature increases the cohesive forces between fluid molecules
decreases due to increase in molecular agitation. Hence, as a result, viscosity
decreases.
1308- Kinematic viscosity depends on density and dynamic viscosity. Both,
density and dynamic viscosity, are independent of acceleration due to gravity.
Therefore, kinematic viscosity is independent of acceleration due to gravity.
1309- Viscosity shows variation for change in temperature and pressure for
compressible fluids. Hence, kinematic viscosity is affected by temperature
and pressure variation.

3- Vapor Pressure:
1310- The vapor pressure of a liquid at a given temperature is given by the
pressure exerted by the saturated vapor on the liquid surface. When the
vapor is saturated, an equilibrium exists between the liquid and the vapor
phases. The number of molecules leaving the liquid surface is equal to the
number of molecules entering the liquid surface. Hence, it is obvious that
vapor pressure will be related to molecular activity and consequently to
temperature. With the increase in temperature molecular activity increases
as a result of which vapor pressure increases.
1311- Vapor pressure is closely related to molecular activity which is in turn
dependent on the temperature of the liquid. With the increase in
temperature molecular activity of a vapor increases slowly at first and then
rapidly. Similar is the nature of variation of vapor pressure.
1312- As the absolute pressure of a liquid goes below its vapor pressure, the
formation of vapor bubbles start. Thus, for boiling to start, the absolute
pressure of a liquid must be less than or equal to its vapor pressure.

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1313- Cavitation occurs whenever absolute pressure of a liquid drops below
its vapor pressure. Dropping of pressure is observed mainly in reaction
turbines and centrifugal pumps.
1314- Whenever the absolute pressure of a fluid drops below its vapor
pressure, bubble formation starts. Again, when the fluid pressure goes above
the bubble pressure, it’ll collapse. This is how cavitation formation takes
place.

4- Thermodynamic Properties & Compressibility:

1315- For process to be adiabatic, there is no heat exchange and no heat
generation within fluid.
1316- As, specific volume remains constant, density remains constant.
Therefore for given temperature there is no change in volume. Hence, the
process is isothermal.
1317- The value of gas constant depends on molecular weight. As the
molecular weight is different, gas constant will be different.
1318- CP is molar heat capacity at constant pressure. As temperature is
increased, enthalpy increases, heat capacity increases.
Same is for Cv, cp is molar heat capacity at constant volume.
However Cp-Cv=R and cp/cv = R
Hence, as Cp, Cv increases R decreases.

5- Fluid Pressure:
1319- Bar is a metric unit of pressure, but it does not fall under the SI units.
One bar is exactly equal to a 100,000 Pascals. This value is taken from the
atmospheric pressure on the earth at sea level.
1320- Hydrostatic pressure varies with the increase in depth. Hydrostatic
pressure is measured from the surface of the fluid because of the increasing
weight of the fluid. The fluid exerts a downward force from the surface of
water thus making it a non-moving fluid.
1321- Manometer is the most preferred measuring device as the pressure is
measured by difference in the column heights of the manometer. It is
expressed in terms of inches or centimeters of fluid making it easier for the
conversion process.
1322- Measurement of liquid in a manometer takes place through
differential pressures by balancing the weight. Thus, it is easier for the

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manometer to measure liquids of lesser density than the heavier ones.
Example of a light liquid is Water.
1323- Manganin wire is the most suitable measurement device for high
pressure liquids. It has a high stability and durability on a long term basis. It
also has a high hydrostatic pressure sensitivity and low strain sensitivity.
1324- Pilot static tube is a system that uses an automatic control scheme to
detect pressure. It has several holes connected to one side of the device.
These outside holes are called as a pressure transducer, which controls the
automatic scheme during fluid flow.
1325- Viscosity is developed due to the relative motion between two
surfaces of fluids at different velocities. It happens due to the shear stress
developed on the surface of the fluid.

6- Pressure Distribution in a Fluid:

1326- Pressure is defined as the force per unit area acting normal to a
surface. The SI unit of force is N and area is m2. Thus, the unit of pressure
will be N = m2.
1327- Pressure (p) is defined as the force (F) per unit area (A) acting normal
to a surface.

Thus,
1328- Pressure is defined as the force per unit area acting normal to a
surface. Both force and area are vectors, but the division of one by the
other leads to a scalar quantity.
1329- Pressure at a point P is equal to ρgh, where ρ is the density and h is
the height of the liquid column. Therefore, ρwater * 1 * g = ρoil * h * g, where
h is the pressure in terms of m of oil.
Thus, h = ρwater / ρoil = 1/0.8 = 1.25.
1330- Mohr’s circle is used to denote shear stress distribution. For fluid at
rest, there is no shear stress. Hence, we cannot draw Mohr’s circle for fluid
at rest.
1331- Principle of Barometer is Hydrostatic law.

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1332- In the inverted U-tube Differential manometer, specific gravity of
manometric fluid used is less than relative to the fluid flowing in the pipes
as the manonmetric fluid is at the top.
1333- Single column manometer directly gives the pressure by measuring
the height in the other limb and due to large cross sectional area of the
reservoir, for any variation in pressure, the change can be neglected.
1334- Manometers are the pressure measuring devices which use the
principle of pressure due to static fluid (i.e. the column height) to measure
the pressure difference.
1335- Differential manometer gives the pressure difference between the
fluid flowing in two pipes with respect to each other.
1336- Inverted U-tube Differential Manometer has lighter manometric
fluid, Hence it is used for measuring the low pressure difference.
1337- Total pressure is defined only for the static fluid at rest. There is no
dynamic component as no motion is involved.
1338- Centre of pressure always lies below the centre of gravity. In certain cases it
may coincide but it can never be above the centre of gravity.
1339- Pressure at every point is different as the depth of different point from is
different.
1340- For differently shaped surfaces, the area and hence position of centroid will
be different. Hence, the magnitude of total pressure and centre of pressure
is dependent on the shape of the submerged plane surface.

7- Manometer:
1341- According to Pascal’s law, the local pressure of a fluid is same in all directions.
Hence, the pressure won’t vary along the x and y direction. The local pressure
will increase with an increase in depth due to the extra weight of water
column above that point.
1342- Absolute zero pressure is the reference used for the measurement of
absolute pressure. Absolute zero pressure is possible (theoretically). Hence,
0 and positive values are possible, but a negative value is impossible.
1343- A high density is favourable because the height of the column required for
the manometer would be low. A liquid with high vapour pressure would be
less sensitive to changes in pressure and may result in a slower rise of the
manometric fluid. Thus, a fluid with low vapour pressure is favourable.

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1344- The height of the manometric fluid in a U-tube manometer in the test column
would fall if there is a positive gauge pressure. The height would increase if
there is a negative gauge pressure. It is possible to measure negative gauge
pressures with a U-tube manometer. However, the negative pressure cannot
fall below -1 Bar.
1345- The height difference may be non-zero when there are multiple immiscible
fluids used in the same manometer. Even though the pressure is same on
both surfaces, the height would be different as the fluid with higher density
will be at a lower height.

8- Bouyancy:
1346- The principal cause of action of buoyant force on a body submerged partially
or fully in fluid is the force equal in magnitude to the weight of the volume
of displaced fluid.
1347- By changing the shape of an object it can be made to float on a fluid even if
it is denser than that fluid. This principle is used in ship building.
1348- Buoyant force acting on the airship decreases as it rises in the air as air at
higher altitude becomes rarer and its density decreases.
1349- As balloon rises in air, pressure acting on it reduces and therefore its volume
increases. Also, a rising balloon ceases rising when it and the displaced air
are equal in weight.
1350- To dive, the submarine tanks are opened to allow air to exhaust, while the
water flows in. When the weight has been balanced so the overall density of
the submarine is equal to the water around it, it has neutral buoyancy and
hence will go down.
1351- The volume of fluid displaced by the body is equal to the actual volume of
body in air. Hence, In case of spherically shaped bodies of uniform mass
distribution and completely immersed in fluid and floating, the centre of
buoyancy coincides with centre of gravity.
1352- Proper explanation for metacentre is:
a) Point at which line of action of force meets the normal axis of body when
it is given angular displacement
b) Intersection of line passing through new centre of buoyancy and centre
of gravity.

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c) point about which body starts oscillating when it is given small angular
displacement
1353- Metacentre does depend on the density. Hence, the metacentric height is
affected by the change in density.
1354- The metacentric height may or may not be zero as metacentre will not always
coincide with centre of gravity.
1355- When it is immersed in such a manner where height is partially immersed,
its stability is most as moment of inertia is most about that axis.
1356- When the weight distribution is around the lower part, the centre of gravity
is at lower portion and hence below the centre of buoyancy which is
condition for stable equilibrium.
1357- The floating body is said to be in unstable equilibrium if the metacentre is
above the centre of gravity.
1358- The floating body is said to be in unstable equilibrium if the metacentre
coincides with the centre of gravity.

9- Types of Fluid Flow:

1359- The velocity in which the water is discharged with a

velocity With time as the water gets discharged,v decreases

as H decreases. Hence, it will be an unsteady flow.
According to the continuity equation, ρAV =constant, where ρ= density, A=
cross-sectional area of flow, V = velocity of flow. Since water is treated as
an incompressible liquid (ρ =constant) and the pipe has a uniform diameter
(A =constant) at a given instant, V will remain constant throughout the
whole cross-section of the pipe. Hence, it will be a uniform flow.
1360- According to the continuity equation, ρAV =constant, where ρ= density, A=
cross-sectional area of flow, V = velocity of flow. For a pipe of a uniform cross-
section, no matter what the rate of flow is, the velocity of flow inside the
pipe will always remain constant. Hence, it’ll always be a uniform flow. It’ll
be a steady flow if and only if the water level is maintained at a constant level
by supplying water at the same rate as it gets discharged, else the water level
will keep decreasing with time leading to an unsteady flow.
1361- The flow inside a pipe can be described by the cylindrical co-ordinate system
(r; θ; z), where r is in the radial direction, θ in the angular direction and z in
the axial direction. For a circular cross-sections, the flow can be taken to be

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independent of θ. Hence, it can be taken aa a two-dimensional flow. Again if
aerage flow parameters are considered to account for the variation in the
radial direction, the flow can be taken as an one-dimensional flow.
1362- When a torque is applied to a fluid particle, it undergoes a rotation. Thus, the
rotation of a fluid particle will alwayds be associated with shear stress. Shear
stress is in turn dependent on the viscosity. Hence, rotational flow occurs
where the viscosity effects are predominant. Since, viscosity effects are
predominant inside the blundary layer, the flow will be rotational in this
region. However, outside the boundary layer, the viscosity effects are
negligible. Hence, flow can be treated as irrotational outside the boundary
layer.
1363- Flows can be characterized as laminar or turbulent on the basis of Reynold’s
number Re = ρvd / μ, where ρ is the density, d is the pipe diameter and μ is
the viscosity. For Re < 2000, the flow will be laminar and Re > 4000, the ow
will be turbulent. For laminar flow, the viscosity effects must be high (μ
should be high) as inside the boundary layer. Outside the boundary layer, the
viscosity effects are negligible. Hence, the flow will be turbulent.

10- Continuity Equation:

1364- According to the Continuity Equation, if no fluid is added or removed from
the pipe in any length then the mass passing across different sections shall
be the same. This is in accordance with the principle of conservation of mass
which states that matter can neither be created nor be destroyed.
1365- Continuity equation is based on the the principle of conservation of mass.
1366- The continuity equation is only applicable to incompressible as well as
compressible fluid.
1367- According to continuity equation,
Area × velocity = constant
Hence, as area decreases velocity increases.
1368- According to continuity equation,
ρ*A*v = constant
Hence, as density and area decreases velocity is bound to increase.
1369- In majority of the fluid flow problems, flow is assumed to be steady.

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11- Newton’s Second Law:

1370- Stagnation point is a point at which a flow field of the local velocity of a
fluid is equal to zero. At this point, the fluid is brought to rest by the object.
When the velocity is zero, the static pressure is maximum.
1371- Compressibility is defined as a measure of relative change in volume of a
fluid. In fluid mechanics, it is also called as isothermal compressibility due
to increase in pressure and temperature.
1372- Kinematic viscosity is a quantity that represents dynamic viscosity of a fluid
per unit density. Density is a major factor that determines the kinematic
viscosity. As the temperature increases, density decreases thereby causing
changes in the density of the fluid.
1373- Density is a major factor that determines the kinematic viscosity. As the
temperature increases, density decreases thereby causing changes in the
density of the fluid. Thus, kinematic viscosity and density are inversely
proportional.
1374- One dimensional flow is a flow in which variations of velocity and pressure
occur along one space coordinate only. A good example of one dimensional
flow is a flow through pipe. During a flow through a pipe, the functions of
velocity and pressure occur along the length of the pipe.
1375- Buoyancy has been explained by Archimedes Principle. The principle states
that the force exerted is directly proportional to the pressure difference.
This equivalent weight of the body immersed is equal to that of the fluid
displaced.
1376- Specific Gravity is defined as the ratio of mass or density of a substance to
that of the mass or density of a reference substance. But, provided that it
has the same volume. It must also have a specified temperature and
pressure.
1377- Heating a substance leads to faster movement of molecules due to which
density decreases. Whereas, cooling a substance leads to a slower
movement of molecules and occupies a smaller volume. Thus, increasing its
density.
1378- Ideal fluids are fluids that have a zero viscosity. This result in a flow called
as inviscid flow. Inviscid flow is non viscous and incompressible since there
is no existence of shear force due to zero viscosity.

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1379- A flow that takes place at a constant speed without the change in cross
section is called a uniform flow. Its parameters remain a constant at any
given point.

12- First Law of Thermodynamics:

1380- First law corresponds to the law of conservation of energy. It states that
energy can neither be created nor destroyed, but can be transformed from
one form to the other. It follows the principle of heat transfer and energy
transfer.
1381- It is a thermodynamic expression which gives a relationship between internal
energy, heat and work done. Work done on the system is positive, and work
done by the system is negative. The standard unit of all these quantities is
Joule.
1382- When there is a high rate of fluid flow, the molecules tend to collide with
each other. At this state, the average translational kinetic energy of the
particles increases. The temperature developed due to this is called as
Kinetic temperature.
1383- The equation for kinetic energy is 0.5mv2, where m= mass and v= velocity.
This equation corresponds to 1.5 KT, where K=Boltzmann’s constant and R=
Gas constant.
1384- When the temperature increases, the amount of molecular interactions also
increases. Using the equation from the first law of thermodynamics, internal
energy also increases with the increase in temperature. Thus, increase in
enthalpy leads to an increase in internal energy.
1385- Entropy is related to a number of microscopic configurations. It can have
some of the most specified macroscopic variables. These macroscopic
variables undergo changes, which lead to a disorder or randomness
1386- This equation was defined by Rudolf Clausius, who defined entropy as a ratio
of reversible heat transfer to that of its absolute temperature. This definition
is also called the macroscopic definition of entropy.
1387- Enthalpy is defined as a measurement of energy in a thermodynamic system.
It is equal to the internal energy plus the product of volume and pressure.
Thus, giving a unit of Joule/kg.
1388- Exothermic reaction is a reaction that releases energy by either light or heat.
It is the opposite of endothermic reactions. In this case, evaporating liquid

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water is an endothermic reaction. Endothermic reaction is a reaction in
which the system absorbs heat from its surroundings.
1389- Photosynthesis takes place by absorbing heat and energy from the
surroundings. Since, endothermic reaction is a reaction in which the system
absorbs heat from its surroundings, the reaction that takes place during
photosynthesis is an endothermic reaction.

13- Classification of Notches and Weirs:

1390- A notch is a device used to measure the flow rate of the flowing liquid,
directly.
1391- The weir is a permanent masonry structure made up of concrete.
1392- The weir is bigger in size than notch.
1393- The MoM (Material of Manufacture) of notch is Metals.

14- Shear Stress and Pressure Gradient:

1394- Shear stress is defined as the force acting per unit area. Thus, the unit of
shear stress is equal to N/m2. Since, 1 Pa =1 N/m2, Pascal is the most suitable
one.
1395- Shear stress is caused due to friction between fluid particles. It is formed due
to the presence of fluid viscosity. Shear stress arises from the force vector
component which is parallel to the cross section.
1396- Shear stress is defined as the force acting per unit area. Shear stresses arise
from shear components(forces), which are pairs of equal and opposite
forces. These forces act on the opposite side of the object.
1397- Shear modulus is also called as modulus of rigidity. It is defined as the ratio
of shear stress to shear strain. Since Young modulus is equal to stress by
strain. The most suitable option is option c. (E= Young’s Modulus, v= poison’s
ratio)
1398- Fluid flow is laminar as it is assumed to be incompressible and Newtonian.
The flow is laminar through the pipe of constant cross section. Thus, there is
no acceleration of fluid in the pipe. Therefore, Hagen-Poiseuille assumed
that fluid flow is laminar.
1399- Pressure gradient is a dimensional quantity. It is expressed in units of
pressure per unit length. It determines which quantity and which direction
the pressure changes around a particular location.

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1400- Volumetric stress is not a basic classification among the type of stresses as it
describes the tendency of an object to deform in all directions. It deforms
when the load acts uniformly in all directions.
1401- According to the continuum mechanics, stress is a physical quantity that
produces internal forces. For example: When a solid bar supports a weight,
each particle of the bar pushes the particles immediately below it. This
happens due to the internal resistive force that is developed due to the stress
on the body.
1402- Hooke’s law states that force is directly proportional to its extension. Hooke’s
law is applicable within the elastic limit, when the body is deformed.
Example: plucking the strings of a guitar.
1403- Factor of safety determines the maximum load carrying capacity. It tells us
how much stronger the system is than it usually needs to be for a particular
specified load. It is the ratio of allowable stress to the actual stress.

15- Flow of Viscous Fluid through Circular Pipes:

1404- In a zero acceleration fully-developed flow in a pipe, the pressure gradually
decreases linearly along the length of the pipe. Hence, the pressure variation
is said to be linear.
1405- High Reynolds number flows (> 4000) are turbulent flows, whereas low
Reynolds number flows (< 2100) are laminar flows. The viscosity coefficient
is a part of the Reynolds number, but isn’t the only criteria for decision.
1406- The question demands the definition and not the commonly used formula of
Reynolds number. Some of them denote the formula of Reynolds number.
The definition of Reynolds number is the ratio of inertia force to viscous force
in a pipe flow.
1407- A flow through a circular pipe is said to be laminar when the Reynolds
number is below 2100. A more viscous fluid would have a higher velocity
coefficient, thus reducing the Reynolds number further at the same
conditions. Hence, the Reynolds number will be well below 2100. Flow will
remain laminar.
1408- The approximate lower critical Reynolds number for Flow in a pipe, flow
between parallel plates, flow in an open channel and flow around the
spherical body are 2000, 1000, 500 and 1 respectively. Hence, the maximum
is for internal pipe flow.

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16- Loss of Head due to Friction in Viscous Flow:

1409- The friction factor(f) depends on the velocity of flow, fluid density, pipe
diameter and the viscosity of the pipe. Roughness of the pipe is also an
important criteria to determine the friction factor.
1410- To calculate the friction factor of a fluid, we use the Blasius equation. This
equation is accurate for values within 5% having Reynolds number less than
105. (Blasius equation: f= 0.079/Re0.25)
1411- Moody chart is a graph of frictional factor(f) vs Reynolds numbers. It gives
various values corresponding to the ‘k/d’ ratios. Where ‘k’ is the measure of
the wall roughness and ‘d’ is the pipe diameter.
1412- Darcy-Weisbach equation relates the head loss and pressure loss due to
friction along a given pipe with a specified length. It contains a dimensionless
friction factor called the Darcy friction factor. The equation was named after
Henry Darcy and Julius Weisbach.
1413- Circular pipes have a diameter treated in a round manner. For a fluid flow
which is laminar head loss is directly proportional to the fluid velocity. Thus,
friction factor is inversely proportional to its velocity. Therefore, the correct
option is ‘64/Re’.
1414- Hydraulic radius is one of the properties of a fluid flow in a channel. It
controls the water discharge. It also determines the amount of work the
channel can do. (Rh=A/P). Thus, it is inversely proportional to loss of head
due to friction.
1415- Hydraulic diameter handles the flow in non-circular channels and tubes. The
most suitable term to calculate the hydraulic diameter for a round tube is
Dh= 4A/P. Where ‘A’ is the cross-sectional area and ‘P’ is the wetted
perimeter.
1416- Minor losses play an important role in calculating the flow, pressure and
energy of the piping system. Fluid that moves through the pipe carries
momentum and energy due to the forces acting on them. Thus, these minor
loses are developed due to valves, pipe diameter and bending.
1417- If the flow rate is doubled, the head loss increases by a factor of four. Since,
the head loss is directly proportional to the square of the flow rate. Option
(d) is the correct option.
1418- Relative roughness is defined as the quantity used to measure the roughness
of the pipe’s surface. It is equal to the average height of the surface

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irregularities divided by the pipe diameter. Therefore, Relative roughness=
ϵ/D.

17- Universal Velocity Distribution:

1419- Aspect ratio in universal velocity ratio is defined as the ratio of free surface
of the fluid flow width to the depth of water. The formula is : Aspect ratio=
b/h. It can also be defined as the ratio of span to the mean chord in an aero
foil.
1420- The maximum velocity occurs at the centre. At the centre, the radius is equal
to zero. The average velocity is obtained by dividing the discharge of fluid.
The discharge takes place across the cross-sectional area of the pipe.
1421- Eddy viscosity is a turbulent transfer of momentum by eddies. It gives rise to
an internal fluid friction. It is in analogous to the action of molecular viscosity
in a laminar fluid flow. Eddy viscosity takes place on a large scale.
1422- Transilient turbulence theory is the method used for parameterizing
turbulence. Its main function is to allow all non-local vertical mixing between
every pair of grid points. It happens in mainly in the vertical column.
1423- Kinematic eddy viscosity is defined as the ratio between Eddy viscosity and
mass density of the fluid. It happens mainly at one hundred times the
molecular kinematic viscosity. It is in the order 1m2s-1.
1424- Eddy diffusion happens due to Eddy motion. This eddy motion is created due
to fluid mixing. The fluid mixture causes the formation of eddies. Eddies can
vary in size from small microscales to subtropical scales.
1425- Reynolds number is a dimensionless quantity. It helps to predict the flow
pattern in fluid mechanics. At low Reynolds number, the flow has a very low
density, due to which the value of Reynolds number is less than 2000.
1426- Reynolds number is a dimensionless quantity. It helps to predict the flow
pattern in fluid mechanics. At high Reynolds number, the flow has a very high
density, due to which the value of Reynolds number is greater than 2000.
1427- Coefficient of friction is defined as the value that shows relationship between
force and the normal reaction. It is mainly used to find out an object’s normal
force and frictional force. Thus, it is equal to 16/Re.

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18- Methods of Determination of Coefficient of Viscosity:

1428- Coefficient of viscosity is defined as the degree to which the fluid resists flow
under an applied force. It is expressed as ratio of shearing stress to the
velocity gradient. The unit is Nsm-2.
1429- With the increase in temperature, the coefficient of viscosity of fluid
decreases. This happens due to the weakening of bonds between the
molecules. Because of its dash pot coefficient, the flow attains peak
deformation.
1430- Coefficient of viscosity is defined as the degree to which the fluid resists flow
under an applied force. It is expressed as a ratio of shearing stress to the
velocity gradient. It has a unit of Nsm-2.
1431- Vibrational viscometer is a viscometer that serves the same purpose as the
other viscometers. But, it is not used for laboratory purposes. It measures
the damping oscillations using a resonator immersed in a fluid.
1432- Coefficient of static friction is defined as the ratio of limiting frictional force
to the normal reaction force. Limiting frictional force is denoted by ‘F’ and
normal frictional force is denoted by ‘R’. Therefore, option ‘c’ is correct.
1433- Coefficient of static friction is defined as the ratio of limiting frictional force
to the normal reaction force. Dividing the dimensions of the limiting
frictional force and normal frictional force, the units cancel out each other
due to which it has no dimensions.
1434- Friction in pipes lead to major and minor loses. It is an economic significance.
It provides a lot of confusions on whether the pipe or duct is entirely closed.
It leads to a high amount of power loss in drawing fluid through the pipes.
1435- The easiest way to measure the coefficient of static friction is by placing the
two objects together and tilting them until one object slides over the other.
Coefficient is related to the angle at which one object starts to slide over the
other.
1436- Coefficient of kinetic friction can be found out by inclined plane method and
horizontal plane method. In case of inclined plane, the block slides down on
an incline with a constant velocity. In the horizontal plane method, the block
does not slide and produces nil friction.
1437- Angle of repose is defined as the steepest angle of descent or dip. It is with
relation to the horizontal plane to which a material can be piled. Example:

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When we pile up stones one over the other, the stones tend to slide along
the heap at a certain point. The angle at that point is the angle of repose.
1438- Angle of repose is defined as the steepest angle of descent or dip. It is with
relation to the horizontal plane to which a material can be piled. The
maximum value for the angle of repose is 90 degrees. It is exactly
perpendicular to the horizontal surface.
1439- Angle of repose is defined as the steepest angle of descent or dip. It is with
relation to the horizontal plane to which a material can be piled. The
minimum value for angle of repose is zero degrees. It lies on the horizontal
surface. Therefore, there is no sliding.

19- Loss of Energy in Pipes:

1440- The major loss for the flflow through the pipes is due to the frictional
resistance between adjacent fluid layers sliding over each other. All other
losses are considered to be minor losses.
1441- The major loss for the flow through the pipes is due to the frictional
resistance between adjacent fluid layers sliding over each other. This
resistance arises due to the presence of viscous property of the fluid.
1442- According to the laws of fluid friction, rf / v (for steady streamline flow) and
rf / v2(for turbulent flow), where rf is the frictional resistance and v is the
velocity of flow.
1443- According to the laws of fluid friction, the frictional resistance is independent
of the pressure for both laminar and turbulent flows.
1444- According to the laws of fluid friction, the frictional resistance is independent
of the nature of the surface area of contact for laminar flows but depends on
the nature of the surface area of contact for turbulent flows.
1445- Frictional resistance is dependent on the nature of the surface area of
contact. But, when the liquid flows at a velocity less than the critical velocity,
a thin stationary film of the liquid is formed on the supporting surface.
Hence, the frictional resistance becomes independent of the nature of the
surface of contact.
1446- Darcy-Weisbach’s formula is generally used for head loss in flow through
both pipes as it takes into consideration the flow velocity whereas Chezy’s
formula is used for open channels as it considers the pressure difference.

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1447- The co-efficent of bend in a pipe depends on all the three parameters –
radius of curvature of the bend, diameter (radius) of the pipe and angle of
bend.
20- Hydraulic Gradient and Total Energy Line:
1448- EGL is obtained by plotting total head at various points along the axis of the
pipe.

where H is the total head, P / γ is the pressure head, z is the potential head
and v2 / 2g is the velocity head. Hence, EGL is also called Total Energy Line
(TEL).
1449- HGL is obtained by plotting piezometric head at various points along the
axis of the pipe.
Hp = P ⁄ γ + z
where Hp is the piezometric head, P ⁄ γ is the pressure head and z is the
potential head.
1450- EGL is obtained by plotting total head at various points along the axis of the
pipe. Since the total head decreases in the direction of flow, EGL will always
drop in that direction.
1451- EGL is obtained by plotting total head and HGL is obtained by plotting
piezometric head at various points along the axis of the pipe.

Hp = P ⁄ γ + z
where H is the total head, P ⁄ γ is the pressure head, z is the potential head,
Hp is the piezometric head, and v2 / 2g is the velocity head.
H = Hp + v2 / 2g Since Hp < H, HGL can never be above EGL.
1452- The vertical intercept between EGL and HGL is equal to the kinetic head.
For a pipe of uniform cross-section, there will be no change in the velocity
of flow across the pipe. Since the kinetic head remian constant, the slope of
HGL will be equal than that of EGL.

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1453- The vertical intercept between EGL and HGL is equal to the kinetic head.
For a nozzle, the cross-sectional area decreases in the direction of flow
leading to an increase in the velocity of flow across the pipe. Since the
kinetic head increases, the vertical intercept between EGL and HGL will
increase.
1454- The vertical intercept between EGL and HGL is equal to the kinetic head.
For a diffuser, the cross-sectional area increases in the direction of flow
leading to a decrease in the velocity of flow across the pipe. Since the
kinetic head decreases, the vertical intercept between EGL and HGL will
decrease.
1455- EGL is obtained by plotting total head at various points along the axis of the
pipe.

where H is the total head, P ⁄ γ is the pressure head, z is the potential head,
, and v2 / 2g is the velocity head.
Hence, there is no relation whatsoever between the slope of EGL and that
of the axis of the pipe.

21- Flow through Nozzles:

1456- This is because there is no attractive force present in the tube for the process
of attraction to occur. Also, the surface of pipes is not an absorbing one,
hence absorption is also ruled out. A pipe is not capable of dissipation of the
molecules. Hence, the right option is deflected.
1457- This is because only with speed of sound Is larger, it’ll be able to compensate
for the speed of gas. Under such situations, the gas density will be able to
stay constant. If they are equal, density will get compressed.
1458- Entropy is defined as the measure of degree of randomness. It is a
thermodynamics quantity. As this nozzle flow deals with thermodynamics,
entropy is the right choice. The other options are not parameters of entropy.
1459- Stagnant point is a point where there is no movement of the fluid. When
there is no movement, the velocity will be 0. Hence the answer is 0.

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1460- Initially the flow has a velocity. In the stagnant state, the velocity is 0. For this
to happen, there should be a deceleration of the velocity. Hence,
deceleration is the answer.
1461- If the angle is more than 10 degrees, there will be a drift amidst the nozzle.
At any angle more than 10 degrees, this separation will occur. But the
minimum value is 10 degrees. So, the answer is 10 degrees.
1462- Anything that flows or runs moves from a region of higher value to lower
value. We can take the example of any physical parameter like pressure,
altitude etc. Hence, here the gas will flow from high to low pressure regions.
1463- This is because this nozzle was invented by Carl de Laval. So, it is also named
after him. Hence De-Laval nozzle is the option.
1464- When the chamber is large, the area is high. Velocity is inversely proportional
to area. So in a large chamber, the flow velocity will be less. It will be
negligible.
1465- Mass flow rate should depend on the velocity. Here Mach number denotes
the velocity. So, the Mach number gives the right answer.

22- Maximum Speed of a Reciprocating Pump:

1466- A reciprocating pump consists of a piston pump, plunger and diaphragm
pump. It is a class of positive displacement. Reciprocating pumps will last for
years and decades.
1467- Bicycle is the pump is the simplest application of the reciprocating pump. It
works on the principle of simple hand operated reciprocating pump. It is used
to inflate bicycle tires and various sporting balls.
1468- Power operated deep well reciprocating pump is divided into single and
double acting. It is classified on the basis of its mechanism. It is distinguished
depending on the function of the piston.
1469- A reciprocating pump is a class of a positive displacement pump. It includes
a piston pump, plunger and a diaphragm pump. It has a long life. Turbine
blades are not an example of the reciprocating pump.
1470- A reciprocating pump is a class of a positive displacement pump. It includes
a piston pump, plunger and a diaphragm pump. It has a long life. Turbine
blades are not an example of the reciprocating pump.

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1471- The main function of the pump is to transfer and convert mechanical energy
of a motor into pressure energy and kinetic energy. It plays an important role
in the transfer of fluid across the pipeline.
1472- Centrifugal pumps are not a positive displacement pump. They are a subclass
dynamic work absorbing turbo machinery. They are used to transport fluids.
It transports fluid by conversion of rotational kinetic energy to hydrodynamic
kinetic energy.
1473- Coriolis concept of measurement of fluid takes place through the rotation
with the reference frame. It is an application of the Newton’s Law. The device
continuously records, regulates and feeds large volume of bulk materials.
1474- Centrifugal pumps are not a positive displacement pump. They are a subclass
dynamic work absorbing turbo machinery. They are used to transport fluids.
It transports fluid by conversion of rotational kinetic energy to hydrodynamic
kinetic energy.
1475- Discharge capacity of the reciprocating pump is lower than that of the
reciprocating pump. Discharge capacity of fluids is defined as the discharge
in terms of the volumetric flow rate. It helps to regulate the flow through a
cross sectional area.
1476- Reciprocating pump is the most suitable high-pressure pumps at moderate
or low discharges. A reciprocating pump is a class of a positive displacement
pump. It includes a piston pump, plunger and a diaphragm pump.

23- Types of Forces Acting in Moving Fluid:

1477- Viscous force is the force that is developed due to resistance of a fluid flow.
Viscous force is equal to the product of shear stress due to viscosity and
surface area of the fluid. It acts in the opposite direction to that of the
acceleration.
1478- Inertial force is the force that has resistance to any physical object that
undergoes a change in its state of motion. Inertial force is the product
acceleration of fluid and its mass. It acts opposite to the direction of
acceleration.
1479- Gravitational force was derived by Newton’s theory of gravitation. It is
defined as the product of mass and acceleration due to gravity of the fluid
flow. It is mainly present in cases of open surface fluid flow.

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1480- Pressure is a force that is applied perpendicular to the surface of an object
over a unit area of force. It is defined as the product of pressure intensity and
cross-sectional area of the flowing fluid. Pressure force is present in case of
pipe flow.
1481- Surface tension is caused due to the attraction of particles in the surface
layer of the fluid in bulk quantities. Surface tension force is defined as the
product of surface tension and length of flowing fluid.
1482- Elastic force is the force that brings a body back to its original position. It is
defined as the product of elastic stress and the area of the flowing fluid.
1483- Coriolis concept of measurement of fluid takes place through the rotation
with the reference frame. It is an application of the Newton’s Law. The device
continuously records, regulates and feeds large volume of bulk materials.
1484- Buoyancy, drag and lift are the three major fluid forces. These forces have
significant importance in various applications. For example: Shotput,
badminton, cricket, baseball, cycling, swimming etc.
1485- The drag force acts in the opposite direction to that of the relative flow
velocity. It acts in the opposite direction with respect to a surrounding fluid
flow. Thus, option Opposite direction is correct.
1486- Drag force is affected by cross sectional area and smoothness. If it is affected
by cross sectional area, then it is called form drag. If it is affected by surface
smoothness, then it is called as surface drag.
1487- The lift force acts in the perpendicular direction to that of the relative flow
velocity. It acts in the perpendicular direction with respect to a surrounding
fluid flow. Thus, option Perpendicular direction is correct.
1488- The drag force acts in the opposite direction to that of the relative flow
velocity. It acts in the opposite direction with respect to a surrounding fluid
flow. Thus, the correct option is D = Cd * A * 0.5 * r * V2.

24- Model Testing of Partially Submerged Bodies:

1489- The process in fluid mechanics that is used to study the complex fluid
dynamics is called as model testing. It is a performance testing. It helps to
test models after a standard scaling. Models are usually smaller than the final
design.

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1490- The pump casting test starts with the inspection of material. It is a Non-
destructive testing method. It is completed after completion of casting
inspection. It depends on the pump design.
1491- After the inspection, the pump casing hydrostatic test is performed. It takes
place only after successful completion of the pump casing inspection.
1492- The pump hydrostatic test is tested at 1.5 times the maximum allowable
work pressure. It can be found out on the pump datasheet. The pump
inspector does not require the calculation of pressure test.
1493- SME stands for Subject Matter Expert. After the inspector has made an
inspection on the finished material. It is further sent to the SME. The main
function of the SME is to approve the finished material.
1494- NPSH stands for Net Positive Suction Head. The main function of the NPSH
test is to measure the ability of the pump. It helps to avoid cavitation at the
inlet section of the pump.
1495- Pump Mechanical run test is performed for nearly 4 hours. Its main function
is to prove that pump works under stable condition. It also helps to
determine if all the variables are within the acceptance range.
1496- Every parameter plays an important role in determining the pump operation.
Density is not a parameter on pump mechanical run test. Each parameter
operate for nearly 10 to 15 minutes.
1497- Pump vibration testing is performed during the performance test at different
flow rates. It also takes place during the mechanical running test at a rated
flow rate.
1498- FFT stands for Fast Fourier Transformation. Depending on the pump design,
housing and vibration it is measured and plotted. FFT is a spectrum which
denotes each data point from minimum to maximum.

25- Dimensionless Numbers:

1499- Diffusivity is defined as the rate of diffusion. It is a measure of particles at
which the fluids or heat can spread. They are measured in different
mediums. It can be defined on the basis of its properties.
1500- The standard symbol for Archimedes number is Ar. Archimedes number in
fluid mechanics deals with the motion of fluids. This takes place due to the
differences in their densities. It was followed by the Archimedes principle.

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1501- The Prandtl number is a dimensionless number. It approximates the ratio of
momentum diffusivity to thermal diffusivity. It can be expressed as Pr = v/
α(1). Where α= thermal diffusivity and v= momentum diffusivity.
1502- The standard symbol for Atwood number is A. Atwood’s number in fluid
mechanics deals with the onset of instabilities in mixtures of fluid. It is due
to the density differences in fluid.
1503- The standard symbol for Blake number is B or Bl. Blake number in fluid
mechanics deals with geology, fluid mechanics and porous media. It is due to
the inertial over the viscous forces in fluid flow through porous media.
1504- The standard symbol for Darcy friction factor is Fd. Darcy friction factor in
fluid mechanics deals with fractions of pressure losses. This is due to the
development of friction in the pipe.
1505- Fanning friction factor is 0.25 times Darcy friction factor. Fanning friction
factor in fluid mechanics deals fraction of pressure losses due to friction in
the pipe.
1506- The standard symbol for Froude number is Fr. Froude number in fluid
mechanics deals with wave and surface behaviour of fluid particles. This is
with the ratio of body’s inertia to gravitational forces.
1507- The standard symbol for Peclet’s number is Pe. Peclet’s number in fluid
mechanics deals with heat transfer. It is defined as the ratio of transport rate
over molecular diffusive transport.
1508- The formula for Knudsen number is λ⁄L. Knudsen number in fluid mechanics
deals with gas dynamics. It is defined as the ratio of the molecular mean free
path length to the representative scale length.

26- Types of Flow in Channels:

1509- The flow characteristics unchanged with time is a steady flow, characteristics
unchanged with space is a uniform flow. Laminar and turbulent flows are
classified with reference to Reynolds number.
1510- Reynolds number – 500 to 600 – Laminar flow
Reynolds number – 500 to 2000 – Transition
Reynolds number – > 2000 – Turbulent flow.
1511- Froude’s number is the ratio of inertia forces and gravitational forces.
Froude’s number is used to classify the flow into critical, sub critical and
super critical.

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1512- Froude’s number = 1 – Critical flow
Froude’s number < 1 – Sub Critical flow
Froude’s number > – Super Critical flow.

27- Specific Energy:

1513- Total Energy = Pressure head + Velocity head + Datum head
Hence energy per unit head is called as total energy.
1514- The graph between total energy and channel position gives the distribution
of energy along the channel and hence the plot is called energy grade line.
1515- In a uniform flow through a channel the depth, slopes and the velocity of
flow remains constant throughout the channel but the datum head may or
may not be the same.
1516- Specific energy is the energy constant throughout the channel and is
estimated with respect to the datum.
1517- Specific energy is constant throughout the channel and is given by

and hence for a given Q and A, E is constant.

28- Relation between Water Surface Slopes and Channel

Bottom Slopes:
1518- Hydraulic slope is defined as a slope of a culvert at a specific flow. It is
classified into the hydraulic regime. It defines the type of solution generated
from the gradual variation in the flow calculations.
1519- Hydraulic curve is defined as curve that is based on the relationship of the
water depth relative to the critical depth and its normal depth. Thus, the
correct choice is hydraulic curve.
1520- Compressible flow is a branch of fluid mechanics that deals with different
types of flow. Its main significance lies in the change in fluid density. It deals
with gas dynamics. Flow is assumed to be isentropic.
1521- Culvert bottom slope is denoted as ‘So’. The culvert bottom slope plays an
important role in determining the hydraulic slope and hydraulic curve of a
fluid flow in motion. It is found using appropriate inlet and outlet conditions.
1522- Critical depth is denoted as Yc. The critical depth plays an important role in
determining the hydraulic slope and hydraulic curve of a fluid flow in motion.
It is found using appropriate inlet and outlet conditions.

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1523- Normal depth is denoted as Yn. The normal depth plays an important role in
determining the hydraulic slope and hydraulic curve of a fluid flow in motion.
It is found using appropriate inlet and outlet conditions.
1524- When So is less than zero, it is called Adverse slopes. The flow conditions for
an adverse slope is similar to that of the horizontal case in that non-existence
state. Adverse slope is always negative.
1525- When So is equal to zero, it is called Horizontal slope. It is denoted as H. The
bed slope follows the manning’s equation to solve for its normal depth. It is
always equal to zero.
1526- When Yo= Yc, it is called a Critical slope. Critical slopes are denoted by the
letter ‘c’. Critical slopes like the other slopes have three depth zones that
help to determine the water surface flow.
1527- When Yn > Yc and So > 0, it is called a mild slope. Mild slope is denoted by ‘M’.
This is a bed slope that has 3 zones with a different set of conditions. This
slope occurs most commonly in the back water curve.
1528- When the slopes have a condition of So > 0 and Yn < Yc, it is called as steep
slope. It is denoted as ‘S’. Steep slope is classified into three zones. These
zone are differentiated depending on their conditions and properties.

29- Characteristics of Surface Profiles:

1529- Surface profile is a measure of flow changes that are developed in the fluid
body. It is developed longitudinally. Thus, the reason for the surface profile
is due to flow changes in the system.
1530- Surface profile is a measure of flow changes that are developed in the fluid
body. It is developed longitudinally. It is divided into normal depth and
critical depth. Thus, the answer is true.
1531- Normal depth is a depth of flow in the channel. It is created when the slope
of the water surface and channel bottom is the same and the water depth
remains the same throughout the entire flow.
1532- Normal depth is a depth of flow in the channel. It is created when the slope
of the water surface and channel bottom is the same and the water depth
remains the same throughout the entire flow. It is formed when gravitational
force is equal to the friction drag.
1533- Normal depth is a depth of flow in the channel. It is created when the slope
of the water surface and channel bottom is the same and the water depth

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remains the same throughout the entire flow. During a normal formation of
a normal depth, there is no acceleration of flow.
1534- Manning’s equation is one of the most commonly used equations governing
the open channel glow. It is an alternative to the Chezy’s equation. It is an
empirical equation that applies to uniform flow in open channels.
1535- Manning’s equation is an empirical equation that applies to uniform flow in
open channels. Manning’s equation is used to calculate normal depth,
roughness, wetted area and the hydraulic radius.
1536- Critical depth is defined as the depth at which the energy is at minimum for
flow discharge. The flow of profile is classified into three zones for a better
understanding. Thus, The correct answer is Critical depth.
1537- Normal depth occurs only for a uniform and steady flow. Normal depth is a
depth of flow in the channel. It is created when the slope of the water surface
and channel bottom is the same and the water depth remains the same
throughout the entire flow.
1538- Subcritical depth occurs when actual water depth is greater than the critical
depth. It is dominated by gravitational forces and behaves in a slow and
stable way.
1539- Subcritical depth occurs when actual water depth is greater than the critical
depth. It is dominated by gravitational forces and behaves in a slow and
stable way. The Froude’s number is less than one during a subcritical flow.
1540- Supercritical depth occurs when the inertial forces behaves as a rapid and an
unstable flow. Supercritical flow transition to subcritical flow takes place
through a hydraulic jump due to high energy loss.
1541- Supercritical depth occurs when the inertial forces behaves as a rapid and an
unstable flow. Supercritical flow transition to subcritical flow takes place
through a hydraulic jump due to high energy loss. It has a Froude number
greater than one.
1542- Critical flow is a flow in which the control flow possesses the minimum
possible energy for a particular flow rate. Critical flow has a Froude’s number
equal to one.

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30- Hydraulic Jump:

1543- Hydraulic pump is a phenomenon in science that deals with hydraulics. It is
observed in an open channel flow. Some of the examples of open channel
flows are rivers and spillways.
1544- Hydraulic pump is a phenomenon in science that deals with hydraulics. It is
observed in an open channel flow. It depends on the initial speed of the fluid.
Thus, option Initial fluid speed is the correct answer.
1545- Hydraulic jump is not possible when the initial speed is less than the critical
speed. There is a transition that is created during the change. The transition
appears as an undulating wave. With the increase in the initial flow, the
transition becomes abrupt.
1546- Open channel flow is a flow that deals with hydraulics in fluid mechanics. It
is a type of liquid flow that flows through a free surface. This free surface is
called as a channel. And since the channel is free, it is called as an open
channel flow.
1547- When the hydraulic jump is dynamic or in a moving form it is called as
positive surge. Hydraulic jump can be stationery or dynamic. Hydraulic jump
can be described using the same analytical approaches.
1548- Fluid speed before the hydraulic jump is supercritical. It is said to be
supercritical because it is faster than the wave speed. It is also called as
shooting speed or superundal.
1549- Hydraulic jump is not possible when the initial speed is less than the critical
speed. There is a transition that is created during the change. The transition
appears as an undulating wave. Fluid height before the hydraulic jump is low.
1550- Hydraulic jump is not possible when the initial speed is less than the critical
speed. There is a transition that is created during the change. The transition
appears as an undulating wave. Fluid height after the hydraulic jump is high.
1551- Hydraulic jump is not possible when the initial speed is less than the critical
speed. There is a transition that is created during the change. Fluid flow
before the hydraulic jump is typically smooth turbulent flow.
1552- Hydraulic jump is not possible when the initial speed is less than the critical
speed. There is a transition that is created during the change. Fluid flow after
the hydraulic jump is typically rough and choppy turbulent flow.

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1553- Subcritical depth occurs when actual water depth is greater than the critical
depth. It is dominated by gravitational forces and behaves in a slow and
stable way. The Froude’s number is less than one during a subcritical flow.
1554- Shallow fluid hydraulic jump takes place during a hydraulic jump that is
created in our sink. It will undergo a smooth flow during the hydraulic jump
as the flow is shallow.
1555- The water that flowing radially slows down due to friction in the fluid. This
happens as the fluid grows shallower, which keeps it dilatory. Due to this, the
Froude number drops to the point where the jump occurs.
1556- Hydraulic pump is a phenomenon in science that deals with hydraulics. It is
observed in in an open channel flow. It depends on the initial speed and flow
rate of the fluid.
1557- Hydraulic jump is not possible when the initial speed is less than the critical
speed. There is a transition that is created during the change. The transition
appears as an undulating wave. Turbidity currents result in internal hydraulic
jumps.
1558- Depth is a parameter that does not play a role in the hydraulic jump. The
internal hydraulic jump have association with temperature induced
stratification, salinity and density differences due to suspended materials.
1559- When the hydraulic jump is dynamic or in a moving form it is called as
positive surge. Hydraulic jump can be stationery or dynamic. Hydraulic jump
can be described using the same analytical approaches.
1560- The hydraulic jump is one of the most used design choices by engineers in
industrial applications. It is used to dissipate energy in spillways and outlets.
A well-defined outlet can produce 60 to 70 percent energy.
1561- The water that flowing radially slows down due to friction in the fluid. This
happens as the fluid grows shallower, which keeps it dilatory. Due to this, the
Froude number drops to the point where the jump occurs.
1562- With the increase in speed of the surface tension, the waves bleed of High
frequency. It makes an undular jump into a dominant form. The flow depth
is just enough that the surface tension can be no longer neglected.
1563- Hydraulic pump is a phenomenon in science that deals with hydraulics. It is
observed in an open channel flow. When it occurs in a rectangular channel.
It is known as classical jump. It is a natural phenomenon.

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1564- Classical jump is a phenomenon in science that deals with hydraulics. It is
observed in an open channel flow. It depends on the initial speed of the fluid.
Classical jump occurs due to the change from supercritical to subcritical
condition.
1565- Hydraulic jump is not possible when the initial speed is less than the critical
speed. There is a transition that is created during the change. This transition
leads to mixing of chemicals, dissipating heat and used in aeration devices.
1566- In a hydraulic jump, the equations are produced by conservation of the
momentum. It is mainly used to apply in equations that have unknown
energy losses. Thus, we must develop the equation for a better
understanding.
1567- Fluid speed before the hydraulic jump is a coagulation chamber. The
hydraulic jumps made by man have primary focuses. The primary focus that
scientists have been focussing on is viscosity.
1568- Hydraulic jump is not possible when the initial speed is less than the critical
speed. There is a transition that is created during the change. The transition
appears as an undulating wave. Fluid height before the hydraulic jump is low.
1569- Hydraulic jump is not possible when the initial speed is less than the critical
speed. There is a transition that is created during the change. Though
momentum is conserved throughout the hydraulic jump, energy is not
conserved.
1570- Length of a hydraulic pump is often difficult to measure due to investigations
that occur due to sudden changes in turbulence. The length of the hydraulic
pump plays an important role in setting up the basins.
1571- Hydraulic jump is not possible when the initial speed is less than the critical
speed. There is a transition that is created during the change. Height of the
hydraulic is similar to its length and is used to know the design of water
structures.
1572- Sub critical depth occurs when actual water depth is greater than the critical
depth. It is dominated by gravitational forces and behaves in a slow and
stable way. The Froude’s number is less than one during a subcritical flow.
1573- Weak jump is a jump that takes place, when the Froude’s number lies in
between 1 to 2.5. The surfaces that result due to weak jump have a very little
energy dissipated.

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1574- An oscillating jump is a jump that takes place when the Froude’s number is
in between 2.5 to 4.5. During this jump, the jet water at the entrance of the
jump fluctuates. It fluctuates from the bottom of the channel to the top of
the channel.
1575- A steady jump is a jump that takes place when the Froude’s number is in
between 4.5 to 9. In this jump the turbulence is confined within the jump
and the location of the jump is susceptible to downstream flow.
1576- A strong jump is a jump that takes place when the Froude’s number is greater
9. In this jump, there is a large difference in the conjugate depths. They are
characterised by different jump actions that result in a high energy
dissipation.

31- Specific Force:

1577- In fluid mechanics, the third principle is given by the conservation of linear
momentum. It is in addition to the continuity of mass and conservation of
energy. They are mostly seen in channel flow problems.
1578- Momentum principle states that all the forces acting in the system result a
change in momentum. It is in addition to the continuity of mass and
conservation of energy.
1579- Frictional force is a force that does not act in the downstream of the fluid
flow. Friction acts in the upstream direction, as friction always opposes the
flow of fluid through a stream developing a viscous flow.
1580- Pressure is a force that is applied perpendicular to the surface of an object
over a unit area of force. It is defined as the product of pressure intensity and
cross-sectional area of the flowing fluid. Pressure force is present in the case
of pipe flow.
1581- Momentum is an expression that is made up of two main functions. These
two terms play a significance role in determining the function. The two terms
are mass flow rate and velocity. Thus, the final formula is mass flow rate *
velocity.
1582- Elastic force is the force that brings a body back to its original position. It is
defined as the product of elastic stress and the area of the flowing fluid.
1583- Specific force is defined as the force that is expressed in terms of its
momentum. It is the momentum of flow passing through a channel of cross

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section per unit time per unit weight and a second is a force per unit weight.
This sum is called the specific force.
1584- It is not possible when the initial speed is less than the critical speed. There
is a transition that is created during the change. Though momentum is
conserved throughout the hydraulic jump, energy is not conserved.
1585- Specific force is directly proportional to the mass flow rate. Specific force is
defined as the force that is expressed in terms of it momentum. It is the
momentum of flow passing through a channel of cross section per unit time
per unit weight and a second is the force per unit weight.
1586- Specific force is inversely proportional to the mass flow rate. Specific force is
defined as the force that is expressed in terms of it momentum. It is the
momentum of flow passing through a channel of cross section per unit time
per unit weight and a second is the force per unit weight.

e) - Farm Machinery:
1- I.C. Engine Components:
1587- There are two ways in which combustion takes place in the cylinder. When
there is a rapid explosion of air- fuel mixture within the cylinder when it is
ignited by spark, is called constant volume combustion and when there is a
slow burning when the fuel is injected into highly compressed heated air,
then it is known as constant pressure combustion.
1588- Octane number is the ignition quality of petrol. Calorific value is the energy
contained by fuel determined by complete combustion. Pre-ignition is the
premature combustion of the fuel air mixture.
1589- L/d, known as stroke to bore ratio, is an important parameter in classifying
the size of the engine. If d < L, it is called under-square engine. If d = L, it is
called square engine. If d>L, it is called over-square engine.
1590- Spark plug is a component to initiate the combustion process. Connecting
rod connects the piston and the crankshaft and transmits the gas forces from
piston to the crankshaft. Camshaft and its associated parts control the
opening and closing valves.
1591- Dugald Clark invented two-stroke engine in 1878.

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1592- The mean piston speed is the average speed of the piston in a reciprocating
engine. It is a function of stroke and RPM. There is a factor of 2 in the
equation to consider one stroke to occur in ½ of a crank revolution.

2- Working Principles of I.C Engine:

1593- For closed system, a change in the energy content is the algebraic difference
between the heat supply, Q, and the work done, W, during any change of
state. The energy may include many types of energies including kinetic,
potential, electrical etc., but from thermodynamic point of view these
energies are ignored and the energy due to rise in temperature is considered.
1594- The end which fits over the crank pin is called the big end of the connecting
rod. Piston a cylindrical part closed at one end which maintains a close sliding
fit in the engine cylinder. Cylinder block is the solid casting which includes
the cylinder and water jackets.
1595- Efficiency ratio is the degree by which the actual thermal efficiency
approaches the ideal cyclic efficiency. Mechanical efficiency is the ratio of
power delivered by the engine to the total power developed within the
engine. An indicated thermal efficiency show what fraction of the heat is
supplied is converted into indicated work.
1596- Rudolf Diesel invented working principle of compression ignition engine.
Gutenberg invented the printing press. Von Guericke was the founder of Air
pump or vacuum pump and Edwin beard budding was the inventor of lawn
mower.
1597- The intake valves are open as a result of the cam lobe pressing down on the
valve stem. The piston moves downward increasing the volume of the
combustion chamber and allowing an air fuel mixture. This step is known as
suction. The charge taken in the cylinder is compressed during the
compression stroke. During power stroke, the high pressure developed due
to combustion of fuel causes the piston to be forced forward or backward at
regular intervals. Exhaust gases go out through exhaust valves during
exhaust stroke.
1598- The first commercially successful internal combustion engine was created by
Etienne Lenoir around 1859. John Baber developed a turbine in 1791. In
1798, John Stevens designed the first American internal combustion engine.
Nikolaus Otto created the first modern internal combustion engine in 1876.

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1599- Valve lifter guide is used in guiding the tappet in motion. Valve stem guide
fits into the cylinder block. Cam gear is fixed at the end of the camshaft to
mesh with the crankshaft gear.

3- Working Principles of 4-stroke Engine:

1600- In a four-stroke engine, the cycle of operations is completed in four strokes
of the piston or two revolutions of crankshaft. Each stroke consists of 180°
of crankshaft rotation and hence a four-stroke cycle is completed through
720° of crank rotation.
1601- Gasoline, a highly volatile fuel is used in SI engines and upper limit is fixed by
antiknock quality of fuel. Compression ratio in SI engine is 6 – 10.
1602- The firing order of a four cylinder engines is 1-3-4-2. The sequence in which
the power stroke in each cylinder of an engine occurs is called firing order.
The arrangement of the crank pin on the crankshaft a design of the camshaft
both determines the firing order.
1603- The interval between successive power strokes in different cylinders of the
engine is called firing intervals. During the first 180° rotation of crankshaft,
the cylinder 1 gets the power stroke, cylinder 2 gets the compression stroke
and cylinder 3 & 4 gets the exhaust and suction stroke respectively.
1604- An IC engine on average is capable of converting just 30-40% of the supplied
energy into mechanical work because a large part of the waste energy is in
the form of heat that is released to the environment through coolant, fins
etc.

4- Diesel Engine vs. Petrol Engine:

1605- The injected fuel is ignited by the heat of the air which compressed by the
piston within the cylinder head. In diesel engine, only air is sucked during
suction stroke.
1606- Entire burnt gases do not out in normal stroke, hence some type of blower
or compressor is used to remove the exhaust gases which are known as
scavenging.
1607- The process of preparing an air-fuel mixture away from the cylinders of an
engine is called carburetion. Lubricant is a substance capable of reducing
friction by making surface smooth. Delivery valve is a high-pressure pump for
feeding fuel to the engine. Nozzle holder accelerates the flow of fuel to
generate thrust.

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1608- Flywheel is a regulator consisting of heavy wheel that stores kinetic energy
and smooth’s the operation of a reciprocating engine. The third option refers
to the function of a piston pin which provides a flexible or hinge like
connection between piston and the connecting rod.
1609- Petrol is a volatile fuel, readily evaporates, so it gets mixed with the air
efficiently. As a result, just a spark is sufficient to produce smooth
combustion in a well-mixed petrol engine. Petrol has a very low flash point
which is opposite in the case of diesel.
1610- The first commercially successful internal combustion engine was created by
Etienne Lenoir around 1859 and the first modern internal combustion was
created in1876 by Nikolaus Otto.
1611- In IC Engines, the main function of piston pin or gudgeon pin is to join the
connecting rod to the piston. By connecting piston pin to the connecting rod
it provides a pivot point between connecting rod and piston.
1612- An inlet manifold is the of an engine that supplies fuel/air mixture to the
cylinders. In contrast, an exhaust manifold collects the exhaust gases from
multiple cylinders into a smaller number of pipes-often down to one pipe.
1613- Tappet clearance is the clearance between the rocker arms and the point
where they rest on the valves. Usually both the surface are flat surfaces. In
four-stroke engines, rockers arms arrangement opens and closes the inlet
and outlet valves.
1614- In an internal combustion engine, the cylinder head sits above the cylinder
on top of the cylinder block. It closes in the top of cylinder, forming the
combustion chamber.

5- 4-Stroke Engine vs. 2-Stroke Engine:

1615- When the piston moves in the cylinder it covers two of the ports, the exhaust
port and the transfer port, which are exactly opposite to each other which
traps a charge of fresh mixture in the cylinder.
1616- The last option is a feature of the ignition coil in which 6 or 12-volt current is
fed in the primary winding and from the secondary winding voltage to the
tune of 2000 volt is tapped.
1617- A governor is said to be hunt if the speed of the engines fluctuates
continuously above and below the mean speed. This is caused by a too

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sensitive governor which changes the fuel supply by a large amount when a
small change in the speed of rotation takes place.
1618- In case of governor running at a steady speed, the inward force acting on the
rotating balls is known as controlling force. It is equal and opposite of the
centrifugal reaction. The formula of controlling force (Fc) of a governor is Fc=
m ω2 r.

6- Working of 2-stroke Engine:

1619- Molar heat capacity is defined as the amount of heat required to raise
temperature of 1 mole of gas through 1°C. For gases, there are two values of
molar heats, i.e., molar heat at constant pressure (Cp) and molar heat at
constant volume (Cv).
1620- The relationship between heat and temperature change is usually expressed
in the form
Q=cm∆T
Where c is the specific heat. The relationship does not apply if a phase
change is encountered, because the heat added or removed during a phase
change does not change temperature.
1621- The crankcase is that part of the engine which supports and encloses the
crankshaft and camshaft. It provides a reservoir for the lubricating oil of the
engine. It also serves as a mounting unit for such accessories as the oil pump,
oil filter, generator, starting motor and ignition components. The upper
portion of the crankcase is usually integral with cylinder block. The lower part
is commonly known as oil pan and usually made of cast iron or cast
aluminium.
1622- Each valve (inlet and exhaust) is opened or closed once during each cycle. A
strong spring with the help of retainer and a key holds the valve tightly
against the seat and thus prevents leakage on the compression and power
stroke. The common face and seat angle of valve is 45° but 30° angle is also
used for intake valves.
1623- 1 kg = 9.8 N
1 N.m. = 1 Joule
1 N. m/s = 1 Joule/s = 1 Watt
1 kg/cm2 = 9.8 * 104 N/m2 = 9.8 * 104 Pa = 98 kPa

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1624- The ratio of length (L) and diameter of bore (D) of the cylinder is called
stroke-bore ratio (L/D). This ratio varies between 1 to 1.45 and for tractor
engines, this ratio is about 1.25.
1625- Timing gear is a combination of multiple gears where in one gear is
mounted at one end of the camshaft and the other gear is mounted at the
end of the crankshaft. In terms of size, Camshaft gear is bigger than the
crankshaft gear and has twice as many teeth than crankshaft gear. For this
reason, this gear is commonly called half time gear.

7- Fuel Supply System:

1626- The percentage of iso-octane (C8H18) in the reference fuel consisting of a
mixture of iso-octane and normal heptane (C7H16), when produces the same
knocking effect as the fuel under test, is called Octane number of the fuel.
1627- The gravity of a fuel or an oil may be expressed as specific gravity or as an
API gravity, a scale devised by American Petroleum Institute. The specific
gravity of a liquid is the ratio of its weight to the weight of an equal volume
of water at 60°F.
1628- Venturi tube is provided to produce low pressure in the throat of the
carburettor. The suction force causes the fuel to rise in the jet. The fuel is
discharged at a rate proportional to the air velocity, available at that point.
1629- Fuel injection pump is a high-pressure pump, which supplies fuel to the
injectors according to the firing order of the engine. It is used to create
pressure varying from 120 kg/cm2 to 300 kg/cm2. It supplies metered
quantity of fuel to each cylinder at appropriate time.
1630- Float chamber is a reservoir to maintain a constant level of fuel in the
carburettor. Fuel comes from the tank to the float chamber. There is a hollow
float provided with a needle. With the level of the fuel going down, the float
with the needle also goes down allowing the fuel to come into the float
chamber from the fuel tank. As the fuel level goes up, the needle closes the
passage and hence a constant level in float chamber is always maintained.
1631- Turbocharger is a turbo-compressor driven by the exhaust gases of the
engines to supply air under pressure to the cylinders of the engine.
Turbocharger is useful because the power output of a diesel engine can be
increased by supplying compressed air to the engine cylinders.

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8- Cooling System:
1632- For satisfactory performance of the engine, neither overheating nor over-
cooling is desirable. Experiments have shown that best operating of I.C.
engine lies between 140°F to 200°F depending upon types of engine and load
conditions.
1633- The purpose of thermostat is to close the water passage, between cylinder
head and the top of radiator, when the engine is cold so that water
circulation is restricted causing the engine to reach operating temperature
more quickly. Thermostats are designed to start opening at 70°C-75°C and
the fully open at 82°C for petrol and 90°C for diesel engine.
1634- The cooling system should be cleaned at suitable intervals to remove Rust
and Scale. One kg of washing soda and 0.5 kg of kerosene oil should be added
to 10 kg of water to make a solution. The radiator should be filled with such
solution and be allowed to remain there for 8 to 10 hours. After this, the
engine should be started and run on medium speed. After 15 to 20 minutes
the solution should be drained out.
1635- The tension of the fan belt should be checked very frequently. If the belt is
very tight, it will cause wear on the pulley of pump and dynamo. The
maximum permissible V-belt sag when applying average finger pressure is
15mm. If it is more than this limit, the belt should be adjusted.
1636- The temperature of burning gases in the engine cylinder reaches up to 1500-
2000°C which is above the melting point of the material of the cylinder body
and head of engine.
1637- Platinum, a metal which has one of the highest melting point, melts at
1750°C
1638- In the case of the ordinary water cooling system where the cooling water is
subjected to atmospheric pressure, the water boils at 212°F. But when water
is boiled in a close radiator under high pressure, the boiling temperature of
water increases to 243°C.
1639- Thermostat valve is a kind of check valve which opens and closes with the
effect of temperature. Standard thermostats are designed to start opening
at 70°C and they fully open at 82°C.
1640- The invention of the automobile water radiator is attributed to Karl Benz.
The first honeycomb radiator is designed by Wilhelm Maybach for the
Mercedes 35hp. Mercedes 35hp is the first successful cooling system vehicle.

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9- Ignition System of I.C. Engine:

1641- Distributor is a device for interrupting the low voltage primary current and
distributing the resulting high voltage current to the engine cylinder in
proper sequence and in proper time.
1642- Electrolyte is the chemical solution used in a battery for chemical reaction.
Usually this consists of about 35% sulphuric acid and 65% distilled water by
weight with a specific gravity of 1.280 in fully charged condition. The
electrolyte level should be 12 to 14 mm above the top edge of the plate.
1643- Specific gravity of the electrolyte should be checked at suitable interval. If
the specific gravity is below 1.225, it should be charged.
1644- Cold plug has a short insulator extending into the cylinder. The short path
dissipates heat quickly, so it is named as cold plug. Hot plug has a
comparatively longer insulator, so the heat has to pass through a longer
path.
1645- Battery leakage is considered excessive if the battery loses more than 1% of
its capacity during 24 hours. To avoid this loss, battery cells should be
regularly cleaned.
1646- A magneto is used to generate an electric current for producing spark in I.C.
engine. A high-tension magneto generates very high voltage needed for
spark plug.
1647- Process of igniting fuel by heat of compression is known as compression
ignition method. Diesel engine is a compression ignition engine. In this
method, no electrical accessory is needed for ignition purpose.
1648- Relief valve is provided to control the quantity of oil circulation and to
maintain correct pressure in the lubricating system. The valve consists of a
ball, held in place over an opening by an adjustable spring.

10- Working Principle of Battery Ignition System:

1649- Primary winding of the transformer is the coil that draws power from the
external source. The primary winding of ignition coil is made of 0.8 mm
diameter copper wire.
1650- Vaporization temperature is the temperature at which the liquid is converted
into vapor without any change in temperature.

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1651- In I.C. engine, the function of spark plug id to make jump of high voltage
current and to ignite the mixture, i.e., charge, within the cylinder. It is used
in petrol engines. the gap of spark plug should be 2.5-2.85 mm.
1652- When an electrolyte is dissolved in a polar solvent (like water), the resulting
solution allows conduction of electricity where in the dissolved electrolyte
separates into cations and anions. A storage battery is a battery which is
rechargeable. Electrolyte used in storage battery consists of 35% H2SO4 and
65% distilled water.
1653- Air-fuel ratio (AFR) is the ratio of mass of air to a solid or liquid or a gaseous
fuel which is present during combustion. This combustion shall take place in
a controller environment such as inside an IC engine or an industrial furnace.
Maximum economy of engine, is obtained at the air fuel ratio is 13.5:1 to
15:1.
1654- Idle speed is the rotational speed of an engine when the engine is idling. An
engine is said to be idle when the engine is not coupled from its drivetrain
and the pedal for throttling is not in a depressed position. Idle speed is
usually measured in RPM (revolutions per minute). At this speed, the engine
will be generating enough power to run smoothly but it won’t be sufficient
to perform any useful work.
1655- Air–fuel ratio (AFR) is the mass ratio of air to a solid, liquid, or gaseous fuel
present in a combustion process. The horsepower of an engine is the power
output of the engine, usually available at the crankshaft. So, if an engine is
rated at 100 HP, it means that at the crankshaft of the engine, 100
horsepower of mechanical power is available when the engine is operating.
1656- Pre-ignition is a condition or situation in which the fuel and air mixture in
spark plugin ignites before the timed spark and this can happen due to
contact with hot surface. So, if the spark plug is over heated or its tip is too
hot, it can result in pre-ignition.
1657- A magnetic ignition system provides current primarily for the spark-ignition
system of a petrol engine. This is achieved by producing pulses of high
voltage for the spark plugs. In such systems, the primary current is produced
by the use of a Magnet.

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11- Fuel Supply System in Ignition or Diesel Engine:

1658- Fuel is consumed by the engine in order to produce energy. The common
fuel for I.C. engines is light diesel oil (22 API degree), high-speed diesel (31
API degree), petrol kerosene (40 API degree), Petrol (13 API Degree).
1659- The quality of the fuel mainly depends upon the volatility of fuel. Calorific
value of fuel is the heat liberated by combustion of a fuel.
1660- Vapor lock is a problem that affects gasoline-fuelled IC engines. It happens
when the fuel changes state from liquid to gas while still in the fuel delivery
system.
1661- Volatility of fuel has considerable effect on the performance of the engine by
affecting- ease of starting the engine, degree of crankcase oil dilution,
formation of vapor lock in the fuel system, accelerating characteristics of the
engine.
1662- Vaporizing temperature of high-speed oil is higher than that of the petrol,
hence petrol vaporizes quicker than diesel oil in the engine cylinder. This help
in easy starting of petrol engines.
1663- Ignition quality is the ease of burning the oil in the combustion chamber.
Octane number and cetane number are the measures of ignition quality of
the fuel.
1664- Octane number is the calculation of knock characteristics of a fuel. The
percentage of C8H18 in the reference fuel consisting of a mixture of iso-octane
and normal heptane C7H16 when is produces the same knocking effect as the
fuel under test is called octane number.
1665- Diesel fuels are rated according to cetane number which is the indication of
ignition quality of fuel. The higher the cetane number the better the ignition
quality of the fuel.
1666- Detonation refers to violent noises, heard in on engine, giving pinging sound
during the process of combustion. It occurs during the process of
combination of the mixture within the cylinder after ignition has taken place.

12- Components of Fuel Supply System:

1667- In spark ignition engines, the fuel tank is placed above the level of the
carburetor. The fuel flows from the fuel tank to the carburetor under the
action.

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1668- This filter is mostly fitted on the fuel lift pump. It prevents dust and foreign
materials from reaching inside the fuel line. It usually consists of a glass cap
with gasket. Heavy dust particles settle at the bottom and clean full flows
ahead.
1669- Carburation is a process of preparing an air fuel mixture away from the
cylinder of an engine on the device in which this process takes place is called
carburettor.
1670- A choke is a butterfly value which is used to provide a richer mixture of air-
fuel for the engine to start in cold condition.
1671- A choke is a butterfly value which controls the volume of air entering into
the venture. A venture is provided to produce low pressure in the throat of
the carburetor.
1672- The main functions of the carburetor are: to atomize the fuel, to regulate the
air fuel ratio at different speeds and loads, to mix the air and fuel thoroughly.
1673- Throttle is a butterfly valve between the mixing chamber of the carburetor
and the inlet manifold of the engine to regulate the quantity of charge. It
may be operated by a hard lever, a foot lever or a governor.
1674- A carburetor mixes fuel and air for internal combustion engines in the proper
air–fuel ratio for combustion. To carburet or carburet means to mix the air
and fuel or to equip with a carburetor for that purpose. Carburetors have
largely been supplanted in the automotive and, to a lesser extent, aviation
industries by fuel injection. They are still common on small engines for lawn
mowers, rototillers and other equipment.
1675- Down draft carburetor is mounted above the intake manifold of the engine
so that the air enters the upper part of the carburetor and the mixture flows
downward into the manifold. These are used mostly on automobile trucks
and stationary engines.
1676- Gasoline pump is a diaphragm type pump and is used in carburetor engine.
It consists of body, cover and lead.
1677- A combustion chamber is a space inside the again, where the combustion of
fuel takes place, in diesel engine, the fuel is atomized, vaporized and burn
inside combustion chamber.
1678- In spark, I.E atomization of fuel takes place in the carburetor and
vaporization occurs in carburetor as well as the inlet manifold.

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1679- Air cell chamber is a space used to trap air in the piston or cylinder during
the compression stroke. Later air blows out into the combustion chamber.
1680- Turbo charger is a turbo compressor driven by the exhaust gases of the
engine to supply air under pressure to the cylinder of the engine.
1681- An Injection Pump, pumps diesel into the cylinders of a diesel engine. Half
crankshaft speed in a four-stroke diesel engine. Its timing is such, that the
fuel is injected very slightly before top dead center of that cylinder’s
compression stroke.

13- Lubrication System:

1682- The viscosity of a fluid is the measure of its resistance to flow. The oil should
be viscous enough to maintain a fluid film between the bearing surfaces. In
order to measure viscosity of lubricating oil, an instrument called Saybolt
viscosimeter is used.
1683- Thermosiphon method is a method of water cooling. It consists of radiator,
water jacket, fan, temperature gauge and hose connections. The system is
based on the principle that heated water which surrounds the cylinder
becomes lighter in weight and it rises upward in liquid column.
1684- In full flow filter the entire quantity of oil is forced to circulate through it
before it enters the engine. A spring-loaded valve is usually fitted in the filter
as a protection device against oil starvation in case of filter getting clogged.
1685- Grease is a semi fluid lubricant, used for slow moving parts. It is useful for
those parts, which are connected and are not easily accessible, such as
universal joints, water pumps, and wheel and axle bearings. Grease consists
of a mixture of mineral oil and metallic soap along with a few other
chemicals.
1686- According to fluid film theory, the lubricant is supposed to act like mass of
globules, rolling in between two surfaces. It produces a rolling effect whereas
according to boundary layer theory, the lubricant is soaked in rubbing
surfaces and forms oily surface over it.
1687- When an oil is heated to its approximate boiling point, vapour is given off
fast enough to burn when contacted with a spark of a flame. The
temperature at which vapour flashes momentarily is called Flash point.

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14- Tractor Classification and Details:

1688- George H. Harris of Chicago invented a tractor or traction engine in 1890. The
tractor word appeared first on record in patent issued on a traction engine.
1689- Generally, 1.5 hectare/HP has been recommended where adequate
irrigation facilities are available and more than one crop is taken. So, a 30-35
tractor is suitable for 40 hectares farm.
1690- Transmission is the speed reducing mechanism, equipped with several gears.
It may be called a sequence of gears and shafts, through which the engine
power is transmitted to the tractor wheels. It consists of tractor to suit
different field conditions. The complete path of power from engine to the
wheels is called power train.
1691- Experimental power take offs were tried as early as 1878, and various
homemade versions arose over the subsequent decades. International
Harvester Company was first to market with a PTO on production tractor,
with its model 8-16 introduced in 1918.
1692- Harry Ferguson patented the three-point linkage for agricultural tractors in
Britain in 1926. He and his colleagues continued to developed several
innovations to this device which made the system workable, effective, and
desirable. In 1938, after almost two decades of trying to sell Henry Ford on
using Ferguson’s system on tractors mass-produced by Ford, Ferguson finally
convinced Ford. The American mass market debut was via the Ford Ferguson
9N in 1939.

15- Principles of Forced Feed System:

1693- Forced feed system of lubrication is a mechanical system of lubricating the
I.C. engines in which a pump forces oil into the engine bearings.
1694- The system is commonly used in high speed multi cylinder engine in tractors,
trucks and automobiles.
1695- Low oil pressure can result due to: weak relief valve spring, worn oil pumps,
cracked oil line, obstruction in oil lines, very thin oil, worn out bearings.
1696- The pump consists of a housing containing two spur gears, one fitted on the
ide shaft and the other on main shaft which gets the drive from camshaft or
crankshaft.

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1697- Usually the oil first enters the main gallery which could be a pipe or channel,
present in the crankcase casting. From the pipe, it goes to each of the main
bearings through holes. From main bearings, it goes to big end bearing.
1698- From main bearing oil goes to big end bearings of connecting rod through
drilled holes in the crankshaft. From there, it goes to lubricate the walls,
pistons and rings.
1699- Oil pressure is an important factor in the durability of most internal
combustion engines and with a forced lubrication system, oil is picked up by
a positive displacement oil pump and is then forced into the oil galleries into
bearings, such as the main bearings, big end bearings and camshaft bearings
or balance shaft bearings.
1700- Wearing of part, oil consumption and operating cost of on engine can be
considerably reduced by proper maintenance of oil filter. The filters used are:
fall flow filter, by pass filter.
1701- A valve stem is a self-contained valve that opens to admit a gas into the
chamber. It is automatically closed to prevent the gas from escaping and kept
sealed by the pressure in the chamber. In force feed system of lubrication,
the valve stem is lubricated through Rocker arm shaft.

16- Tillage System:

1702- Primary tillage is normally designed to reduce soil strength, cover plant
materials, and rearrange aggregates. The operations performed to open up
any cultivable land with a view to prepare a seed bed for growing crops is
known as Primary tillage.
1703- The main implement for primary tillage is plough used for ploughing
operations. Ploughing is the primary tillage operation, which is performed to
cut, brake and invert the soil partially or completely. Ploughing essentially
means operating the upper crust of the soil, breaking the clos and making
the soil suitable for sowing seeds.
1704- Stubble type’s relatively abrupt curvature lifts, breaks and turns the furrow
slice. Its curvature is not gradual but it is abrupt along the top edge. This
causes the furrow slice to be thrown off quickly, pulverizing it much better
than the other types of mouldboard.
1705- Landside helps to resist the side pressure exerted by the furrow slice on the
mouldboard. It also helps in stabilizing the plough while it is in operation.

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Landside is fastened to the frog with the help of plough bolts. The rear
bottom end of the landside is known as heel which rubs against the furrow
sole.
1706- Jointer is a small irregular piece of metal having of a shape similar to an
ordinary plough bottom. It looks like a miniature plough. The small furrow
slice that is cut from left and upper side of the main furrow slice and is
inverted so that all trashes on the top of the soil are completely turned down
and buried under the right-hand corner of the furrow.
1707- Turn Wrest plough, while moving in one direction the plough throws the soil
in one direction and at the return trip the direction of the plough is changed,
thus the plough starts throwing the soil in the same direction as before.
1708- Disc angle is the angle at which the plane of the cutting edge of the disc is
inclined to the direction of travel. Usually, the disc angle of good plough
varies between 42° to 45°.
1709- Vertical disc plough is also known as Harrow plough or One-way disc plough.
Its action is intermediate between regular disc plough and disc harrow. It has
a frame, wheel arrangement, and depth adjusting devices.
1710- Rotary plough is also called rotary tiller. It is suitable for shallow cultivation
and weed control. The rotary tiller consists of a power-driven shaft on which
knives or tynes are mounted to cut the soil and the trash.
1711- A strip of land left unploughed at each end of the field for the tractor to turn
is known as head land. The head land is about 6 meters wide for tractor
plough.

17- Mouldboard Plough:

(It is tractor operated implement and it consists of share point, share,
mouldboard, landside, and frog, shank, frame and hitch system. The
working of the plough is controlled by hydraulic system of the
tractor. Mould board plough is a primary tillage implement.)
1712- The share is made of chilled cast iron or steel. The steel mainly consists about
0.70%-0.80% of carbon besides other minor elements.
1713- The share is made of chilled cast iron or steel. The steel mainly consists about
0.50%-0.80% of manganese besides other minor elements.

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1714- Slipnose share is a share in which the point of share is provided by a small
detachable piece. It has the advantage that share point can be replaced as
and when required.
1715- Sod or breaker type is a long mouldboard with gentle curvature which lifts
and inverts the furrow slice. It turns over thickly covered soil. This is very
useful where complete inversion of soil is required.
1716- Gunnel is the vertical face of the share which slides along the furrow wall. It
takes the side thrust of the soil and supports the plough bottom against the
furrow wall.
1717- Slip share is one piece share with curved cutting edge and no additional
parts. It is a common type of share used by the farmers. It is simple in design,
but has a disadvantage that the entire share has to be replaced if it is worn
out due to constant use.
1718- It is the maximum clearance between the landside and a horizontal plane
touching point of share at its gunnel side and heal of land side. This suction
helps the plough to cut the proper width of furrow slice. This clearance varies
according the to the size of the plough, which is the distance from wing of
the share to the line joining the point of share and heel of landside.

18- Disc Plough:

(Disc plough is used for primary tillage and is especially useful in
hard and dry, trashy, stony or stumpy land conditions and in soil
where scouring is a major problem. Features: It consists of a frame,
tynes with reversible shovels, hitch system and heavy-duty springs.)
1719- Chisel plough is a plough used to cut through hard soils by means of a number
of narrow tynes. It is useful for breaking hard layers of soil just below the
regular ploughing depth.
1720- Draft increases with increase in speed in most of the tillage implements. This
may be due to rapid acceleration of any soil that is moved appreciably.
1721- Whenever a plough works round a strip of ploughed land, it is said to be
gathering, whereas whenever a plough works round a strip of unploughed
land, it is said to be casting.
1722- In starting at the center method a small plot of land is marked in the middle
of the field and it is ploughed first. After that, the plough works round this
small plot and the entire plot is completed. In starting at the outer end

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tractor starts ploughing at one end of the field and then moves on all sides
of the plot and comes gradually from the sides to the center of the field.
1723- Centre of resistance is the point at which the resultant of all the horizontals
and vertical force acts. The center lies at a distance equal to 3/4th size of
plough from the share wing.

19- Harrows:
(A harrow is a farm tool. It is an implement for breaking up and
smoothing out the surface of the soil. In this way it is different from
a plow, which cuts deeper into the soil. A plow also lifts up the soil
and tips it over, but a harrow works mostly by cutting into the soil
and breaking it up).
1724- Spool is just a device for keeping the discs at equal spacing on the axle. It is
usually cast in special shapes and sizes and is generally made of cast iron.
1725- Offset Disc harrow has two gangs in tandem and two fitted one behind the
other. The discs of both gangs face in opposite directions.
1726- Disc is a circular, concave revolving steel plate used for cutting and inverting
the soil. Disc is made of high grade heat treated hardened steel. Tractor
drawn disc harrows have concave discs of size varying from 35 to 70 cm
diameter.
1727- Usually transport wheels are provided for easy movement of the harrow
from place to place. The size of the harrow is determined by the maximum
width of cut of the soil. The weight of the disc harrow varies between 80 to
100 kg.
1728- The lever of the gang angle mechanism is usually made of mild steel flat with
wooden handle. The gang angle can be adjusted approximately in the range
from 0° to 27° only.
1729- Acme harrow is a special type harrow having curved knives also known as
knife harrow. The front part of the knife compacts the soil and crushes the
clods. A good pulverization is obtained by this harrow easily.

20- Cultivators:
(A cultivator is any of several types of farm implement used for
secondary tillage. One sense of the name refers to frames with teeth
that pierce the soil as they are dragged through it linearly. Another

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sense refers to machines that use rotary motion of disks or teeth to
accomplish a similar result).
1730- Shovel is usually of reversible type. The width of the shovel varies between
50 to 75 mm and is made of steel having carbon content ranging from 0.5 to
0.6%. The cutting angle varies in the range of 15° to 20°.
1731- A seed funnel usually mad of mild steel sheet of about 0.70 mm thickness is
fixed to the handle. At the bottom of the funnel there are three openings at
120° to each other leading to the seed tubes.
1732- Duck foot cultivator is a type of rigid cultivator which is used mostly for
shallow ploughing, destruction of weeds and retention of moisture. The
sweeps are fabricated from high carbon steel. Number of sweeps can be
reduced according to requirement. Usually this cultivator is about 225 cm
long, 60 cm wide with 7 sweeps.
1733- Generally, rigid tines do not deflect during the working in the field. These
tines are bolted between angle braces and tried to the main bars by use of
good quality clamps and bolts. So, we can change the spacing simply by
loosening of the bolts, adjusting the braces and then tightening the bolts.

21- Sowing Equipment – Seed Metering Mechanism:

1734- Dibbling is the process of placing the seeds in holes made in seed bed and
covering them. In this method, seeds are placed in holes made are definite
depth at fixed spacing. The equipment used for dibbling is called Dibbler.
1735- Check row method is a method of planting, in which row to row and plant to
plant distance is uniform. In this method, seeds are planted precisely along
straight parallel furrows. The rows are always in two perpendicular
directions.
1736- Internal double run type is a seed metering device in which the feed wheel
is provided with fine and coarse ribbed flanges. It consists of discs, mounted
on a spindle and housed in a casing fitted below the seed box.
1737- Cup feed mechanism consists of cups of spoons on the periphery of a vertical
rotating disc which picks up the seeds from the hopper and delivers them
into the seed tubes.

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22- Sowing Equipment – Furrow Openers:

1738- Brush feed type is a seed metering mechanism in which rotating brush
regulates the flow of seed from the hopper. A number of bullock drawn
planters in the country have brush feed mechanism.
1739- Shoe type furrow opener works well in trashy soils where the seed beds are
not smoothly prepared. Shoe is made of carbon steel having minimum
carbon content of 4% with a minimum thickness of 4mm.
1740- Seed tube is which carries the seeds from the metering device to the boot.
Seed tubes are provided at the lower end of the feed cups. They conduct
seeds from feed cups to the furrow lines through suitable boots and furrow
openers. Polythene or rubber tubes are also used for this purpose. The
minimum diameter of seed and fertilizer tube is 25 mm.
1741- Single type furrow opener consists of one concave disc. It consists of a curved
disc made of hardened steel. It is set at an angle which while operating, shift
the soil to one side making a small ridge. The disc is kept clean by two
scrapers, one toe shaped at the convex side and one ‘T’ shaped at the
concave side.
1742- The seeds from the hopper are received by the rotating plates. The plate
moves under Cut-off which allows only those seeds which are occupied in
the cells. Cut-off is a mechanism which cuts off extra seeds from the cells of
the feed mechanism.
1743- Potato planter is used for planting of potatoes. The semi-automatic potato
planter consists of a hopper, metering disc and furrow openers. It may plant
in 2-4 rows. Its field capacity may be 0.15-0.25 ha/hr. It may be run by a 20-
25 hp tractor.
1744- Zero till drill consists of a 9-tyne seed-cum-fertilizer drill with a rotary blade
attachment, operating in front of the furrow openers. The rotary attachment
consists of a frame with nine flanges welded to the rotor. Each flange has six
C-type blades.
1745- The automatic potato planter, which is a potato dropping mechanism
contains a hopper and cups. The cup picks up the graded potatoes and carries
to furrow opener spout and releases in the furrow. The fertilizer and
pesticides can also be placed simultaneously. It can plant 2-4 in rows. Its
capacity may be 6000-14000 potatoes/hour.

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23- Sowing Equipment – Rice Transplanter:

1746- For paddy, one should do the transplantation when they are at 4-5 leaf stage
which is approximately about 15-20 cm height. We should not delay beyond
this otherwise it leads to poor tillering i.e., early flower of the main tillers
which will reduce the overall yield of the crop.
1747- Under good management and adequate nitrogen levels, the optimum
spacing should be around 20*10 cm2. With excellent cultural practices, the
spacing may be slightly wider, say 20*15 cm2 but under sub normal
conditions, the spacing should be slightly narrower i.e. 15*10 cm2.
1748- Planting geometry of 15*15 cm to be maintained in organic rice cultivation
so that 1 mm2 area has about 50 hills. Square geometry has smothering
effect on weeds.
1749- One should do transplanting of two to three seedlings per hill under normal
conditions. If we use more seedlings, it will cost more but will not give the
extra benefit as compared to the extra cost.
1750- In case of shallow planting, the tiller buds which are formed at the basal node
area are suppressed in the soil. Hence, the transplantation depth of the
paddy seedlings should be 2-3 cm only.
1751- During late 19th century, an attempt was made to mechanize the rice trans
plantation system. However, Rice trans plantation system was developed in
Japan in 1960s and it evolved and progressed at a rapid pace during 1970s
and 1980s.
1752- A rice trans planter consists of seedling tray, the seedling tray shifter and
pickup forks. The seedlings are fed to the seedlings tray which acts like a shed
roof for the seedlings.
1753- The spacing of seeds or hills in the row is determined by the ratio of linear or
peripheral speed of the cells to the forward speed of the planter and by the
distance between the cells in the metering unit. The accuracy of the planter
depends upon several factors such as: speed of seed plate, shape of hopper
bottom, shape and size of cells, uniformity of seed size.

24- Harvesting Equipments – Power Transmitting Unit Mower:

1754- Tractor drawn semi mounted or mounted type mowers are operated by PTO
shaft. In this case, the cutting mechanism is driven independently of the

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forward speed of the mower. A shaft is connected with the PTO shaft which
drives a pulley with the help of a universal joint.
1755- In bullock drawn mowers, the power transmitting unit consists of axle, gears,
crank wheel, crankshaft and pitman. The transport wheel gives power to the
axle from where the power is transmitted through the gear box. There is a
ball and socket arrangement to connect the knife with the pitman. The
operator controls the driving unit with the help of a dog clutch.
1756- Cutter bar is an assembly comprising of fingers, knife guides, on wearing
plates and shoes. It is used for cutting grasses and forge. It is made of high
grade steel. It works like a knife. There are ledger plates provided with the
knife guard, on which the knife moves. Knife clips hold the sections down
against the ledger plates. Knife clips are placed with wearing plates spaced
20 to 30 cm apart.
1757- A mower knife is said to be in proper registration when the knife section
stops in the centre of its guard on every stroke i.e. the centre of the knife
section is at the centre of the guard, when it is in opening condition.
1758- A shoe on each end of the cutter bar is always provided to regulate the height
of cut above the ground. The inner shoe is larger in section and is placed at
the inner end of the cutter bar. The outer shoe is placed at the outer end is
smaller in section.

25- Plant Protection Equipments – Sprayers:

1759- Power sprayers are operated with internal combustion engines. The prime
mover capacity varies from 1 to 5 hp.
1760- The pressure pump, in the Power sprayer, is operated by a small power unit
ensuring a constant steady pressure from 20 to 55 kg/cm2. These machines
are usually portable type.
1761- Agitators are needed to agitate the liquid of the tank. Horizontal shaft may
be used with flat blades rotating at about 100-200 rev/min. Paddle tip speeds
in excess of 2.5 m/sec may cause foaming.
1762- Fan nozzle is a nozzle which forms narrow elliptical spray pattern. In this
type, the liquid is forced to come out as a flat fan shaped sheet which is then
broken into droplets.

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1763- Nozzles on field sprayers have spray angles of 60° to 90° but high-pressure
nozzles have smaller angles. Operating pressure below 1.5 kg/cm2 is
undesirable the nozzle does not work satisfactorily.
1764- Solid cone nozzle covers the entire area at small range. The construction is
similar to hollow cone nozzle with the addition of an internal jet which strikes
the rotating liquid just within the orifice of discharge.
1765- Steel tank is widely used to prevent corrosion. Plastic tanks are also getting
popular due to freedom from corrosion and ease of moulding into smooth
shapes.
1766- Nozzle is used to break the liquid into desired spray and deliver to plants. The
body of the nozzle and the screw cap hold all the other parts in place. The
disc has a number of holes including one hole in the center and they are
usually numbered from one to ten to denote the diameter of the hole.
1767- The ultra-low volume sprayer has a motor powered by 6 to 122 V battery. To
the motor is attached a spinning disc, having grooves or teeth and rotates at
a very high revolution per minute (4000-9000).
1768- Hand atomizer type sprayers are provided with single action or continuous
action air compression pump. When the air is compressed, it is passed over
the end of a suction tube which extends down into the spray material. A
common type is Mysto hand sprayer and Filt gun.
1769- Knapsack type is a sprayer with the fluid container carried on the back of the
operator. It is a compressed air type sprayer which has an air tight chamber.
An air pump is mounted on the chamber. The container is filled 3/4th full so
as to leave enough space to compress a good volume of air above the spray
material.
1770- Rotary pump is commonly used for low pressure sprayers. It may be Vane
type or Propeller type. Rollers may be made of nylon, steel or carbon. When
the rollers are in operation, they are held against the case by centrifugal
force. Rotary pumps are compact and cheap.
1771- Hand atomizer type sprayers are provided with single action or continuous
action air compression pump. When the air is compressed, it is passed over
the end of a suction tube which extends down into the spray material. When
the compressed air escapes through the nozzle, it carries the spray material
along with it. Such sprayers are commonly used for household work, nursery
and kitchen gardens.

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1772- When the chemical travels through the rubber hose from the power sprayer,
the pressure is lower at the end of the hose than at the discharge part of the
power sprayer. Such pressure loss is mainly caused by the friction of the
moving chemical against the wall of the hose.
1773- Pump efficiency is defined as the ratio of water horsepower output from the
pump to the shaft horsepower input for the pump. Water horsepower is
determined by the flow rate and pressure delivered to the pump from the
power unit, which is usually an electric motor or internal combustion engine.
1774- Total head is determined by measuring the distance from the source water
surface to the output of the pump is producing at the pump outlet. If this
value is measured for a centrifugal pump, the distance from the water
surface to the pump outlet needs to be measured.

26- Traction and Traction Theory:

(Traction can also refer to the maximum tractive force between a
body and a surface, as limited by available friction; when this is the
case, traction is often expressed as the ratio of the maximum tractive
force to the normal force and is termed the coefficient
oftraction (similar to coefficient of friction).
1775- Traction is a force which generated between tyre and soil surface and due to
this force only, tractor pull loads and move forward. More technically, when
powered wheel try to move on soil, this wheel’s force (wheel torque/wheel
radius) try to break the soil.
1776- The power developed in engine, finally goes to wheel or tracks, which move
the tractor with or without an attached load. During the movement of
wheels, some slip occurs, which causes reduction in speed.
1777- Traction is the force in the direction of travel, developed by the traction
device medium and transferred to the vehicle. The power developed in
engine, finally goes to wheel or tracks, which move the tractor with or
without an attached load.
1778- The coefficient of traction is defined as the usable force for traction divided
by the weight on the running gear. It can also be defined as the ratio of the
total force output of the traction device in the direction of travel to the
dynamic weight on traction device.

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1779- Tractive efficiency is the ratio of the drawbar power to axle power and can
be estimated wen the slip is known. TE of a wheel can be predicated using a
series of equations that take into account tire dimensions, soil conditions,
slip, etc. It is the ratio of output power to input power, expressed in
percentage.
1780- Wheel slip is the relative movement of the wheel or track in direction of
travel for a given distance under load and at no load condition.
1781- Rim pull is a term which is used to designate the tractive force between the
rubber tyres of the driving wheel and the surface on which they travel. The
coefficient of traction is high enough to eliminate tyre slippage.
1782- Track frame consists of two heavy endless metal chains moving on two iron
wheels. These chains are called tracks. One wheel carries sprockets and acts
as river unit, the other wheel serves as an idler.
1783- Pneumatic tyres are used for common tractors. When such a tractor moves
over soil, it has to overcome the rolling resistance R.
1784- A tram is a passenger vehicle powered by electricity conveyed by overhead
cables and running on rails laid on a public road. The motor depends on the
type of locomotive and the torque or tractive effort required.
1785- The rolling resistance due to soil compaction can be approximated by
assuming that the energy required to overcome the rolling resistance is equal
to the work done in deforming the soil.

27- Tractor Tyre and Front Axle:

1786- Tires provide a footprint, designed to match the weight of the vehicle with
the bearing strength of the surface that it rolls over, providing a bearing
pressure that will cause the deformation of the surface excessively.
1787- The tyre size is defined as Width of tyre upon Ratio of tyre, Type of tyre,
Diameter of rim to be used. This could be understood by an example,
215/60R15 where, 215 is the width of the tyre in millimeters. 60 is the tyre
profile. Radial construction is denoted by R. Diameter of the wheel rim in
inches is 15.
1788- Inflation pressure in rear wheel of tractor varies between 0.8-1.5 kg/cm2.
1789- Cold inflation pressure is the pressure of tires when tires are warmed up and
before the car is driven. The recommended cold inflation pressure is written
on the owner’s manual and attached to the vehicle.

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1790- In traction, the front wheel acts as Steered wheel.
1791- Toe-in is a slight forward convergence of a pair of wheels so that the wheels
are closer together in front than from behind.
1792- Ground clearance is the amount of clear space between the lowest part of a
vehicle’s frame and the ground.
1793- The force which can be used for traction divided by the weight on the
running gear is known as the coefficient of traction:
Usable traction = coefficient of traction x normal force.
1794- Camber angle is the angle made by the wheels of a vehicle; it is the angle
between the vertical axis of the wheels used for steering and the vertical axis
of the vehicle viewed from the rear or front.
1795- Tractor is a self-propelled power unit having wheels for operation on
agricultural implements and machines including trailers. Tractor engine is
used as a main mover for active tools through PTO or belt pulley. Low ground
pressure is not suitable for wheel type tractor.
1796- Excessive vibration of tyre is Wobbling.
1797- Camber angle is the angle between the vertical axis of the wheels used for
steering and the vertical axis of the vehicle viewed from the rear or front.
The range of Camber angle is 2° to 4.
1798- By 1933, tractor companies offered models with rubber tires which were
already mounted on rims. Blacksmith shops’ saw a growth in their business
when they started retrofitting steel wheels to rubber ones. 95% of new
tractors rode on rubber wheels by 1940.

28- Tractor Testing:

1799- The principal aim of tractor is to make available to buyers the data on power
output and performance of the tractor. The test would provide a general
identification and description of the tractor and its usual accessories.
1800- Test at maximum power test is done with the help of a suitable
dynamometer. The maximum power quoted in the report should be the
average of the readings taken during the two hours test. If the power
variation exceeds 2% from average value, the test should be repeated. If the
same condition persists in further tests, it should be recorded in the report.
1801- In the governor controlled zone, the torque, speed and hourly fuel
consumption should be noted, corresponding to the power of the engine.

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The readings are taken at no load, one quarter load, half load, three quarter
load and full load, corresponding to maximum power and at 85% of the
torque.
1802- Drawbar pull is determined by means of suitable dynamometer, inserted at
the hitch between the tractor and the pulling load. For drawbar testing, the
load on the back of the tractor has to be varied and hence a loading car is
used.
1803- The slope of the land has got effects on tractive effort and stability of the
tractor. To evaluate this effect, the center of gravity of the tractor should be
determined with and without ballast with fuel tank full, and lubricating oil up
to desired mark. A weight of 75 kg is put on the seat of the driver to replace
the driver.
1804- The diameter of the circle described by the median plane of the outermost
steered wheel while moving at speed not exceeding 2 km/hr, with the
steering wheel in full locks, is called turning circle.
1805- Brake test is done in cold condition as well as in hot condition. A brake is
considered cold when its temperature is below 80°C. An artificial horizontal
track is prepared, which gives good grip for tyres.
1806- Brake test is done in cold condition as well as in hot condition. A brake is
considered cold when its temperature is below 80°C. An artificial horizontal
track is prepared, which gives good grip for tyres. It is desirable to test the
brake at maximum speed or at 25 kmph, whichever is lower. Test should be
done in ballasted and unballasted conditions.
1807- The tractor shall be put on a level ground. The air cleaner should be cleaned
and filled with normal oil. The engine shall be operated at full governed
speed for 15 minutes with continuous acceleration and deacceleration. If
there is no oil pull over with the tractor in level position the tests shall be
repeated with tractor tilted 15° to either side.
1808- The tractor shall be put on a level ground. The air cleaner should be cleaned
and filled with normal oil. The engine shall be operated at full governed
speed for 15 minutes with continuous acceleration and deacceleration. If
there is no oil pull over with the tractor in level position the tests shall be
repeated with tractor tilted 15° to either side and then 30° forward and
backwards with direction of travel.

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29- Farm Tractor – Power Tiller:

(Power Tiller or Heavy Tiller is an innovative machine used for
cultivation, tillage, showing and weeding that contains a self-set of
blades set up with a powerful engine. ... Power tiller equipment is
two-wheeled farm equipment that fitted with a rotary tiller performs
smoothly all farm operations.)
1809- A power tiller is basically a set of blades (called tines) that are mounted in a
wheeled housing and powered by an electric motor or gasoline engine.
1810- The concept of power tiller came in the world in the year 1920. Japan is the
first country to use power tiller was designed in the year 1947.
1811- An internal combustion engine is a heat engine where combustion of a fuel
occurs with an oxidizer which is in a combustion chamber that is an
important part of the working fluid flow circuit.
1812- In power tiller, the tilling attachment receives the power from tilling clutch.
1813- Tillage is the agricultural manipulation of soil by mechanical agitation of
various types, such as digging, stirring, and overturning.
1814- A friction clutch is a clutch in which the drive is conveyed by the friction
between attached surfaces of the driven and driving shafts. These surfaces
are lined with cork, asbestos, or other fibrous material.
1815- A form of dynamometer for measuring the power a motor exerts. A clamp
around the revolving shaft of the motor resists the motion by its friction, the
work is absorbed being established by observing the force required to keep
the clamp from revolving with the shaft.
1816- Clutch delivers power from the engine for a smooth movement (less
vibration) of the vehicle. It basically transmits the torque generated from the
engine to the drivetrain.
1817- A power tiller is generally used for 10 years. After that duration, the body of
the tiller including the blades/tines are worn out and will not be efficient.
1818- A V-belt is the rubber belt that drives the alternator, air conditioning
compressor, power steering pump and water pump. It’s called a V-belt
because of its “V” shaped cross-section. All belts wear out over time and
need to be replaced.
1819- The wheel receives the power from a Steering clutch in a power tiller. Clutch
delivers power from the engine for a smooth movement (less vibration) of

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the vehicle. It basically transmits the torque generated from the engine to
the drivetrain.
1820- The engine transmits the power first to main clutch in a power tiller. Clutch
delivers power from the engine for a smooth movement (less vibration) of
the vehicle. It basically transmits the torque generated from the engine to
the drivetrain.

30- Mechanical Power Transmission – Belt Drive:

1821- V-belts are so named because they run over pulley having V-shaped grooves.
V-belts have trapezoidal cross- section.
1822- Small pieces of belts are joined together to make a long belt. Belt pieces are
joined either by fastening, stitching or connecting or in only one direction.
1823- V-belt have V-shaped grooves and the angle between is known as groove
angle. It varies from 32° in small pulleys to 40° in larger pulleys.
1824- Speed cones are pulleys having several steps of different diameters. The
belts move on these steps.
1825- Idler pulley, slide rail and tilting plate are three different devices for adjusting
tension of the belts.

31- Mechanical Power Transmission – Chain and Sprocket

Drive:
1826- Chain and sprocket are used to transmit motion and power where two parallel
shafts are spaced apart at short distances. It is a positive drive.
1827- Hook link chain is used for external drive such as potato digger when power
requirement is low and speed is also low.
1828- Sprockets are tested wheel, that is, have projecting teeth of special profile and fit
into the corresponding recesses in the limbs.
1829- Roller chains are made of high grade steel and components are hardened and
polished and are used for higher speed and power transmissions.
1830- Pintle chains are used for heavy duty, slow speed rate in any exposed atmosphere
and is made of malleable links, held together by suitable pins.
1831- Numbers of standard roller chains with length are:
35-1 cm
40-1.3 cm
50-1.6 cm
60-1.8 cm
80-2.5 cm.
1832- These chains are usually used for small center distance of up to 2 m but sometimes
may also be used for long distance of up to 8 meters.

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1833- As no slip takes place during chain drive, perfect velocity ratio is obtained in chain
drives and these are positive displacement drive.

32- Mechanical Power Transmission – Gear Drive:

1834- Worm gear is used when two shafts are at right angles but not intersecting
to each other, not to be confused with bevel gear where the axis of two
shafts are at right angles and can intersect each other.
1835- Helical gear is used for transmitting power between parallel shafts and the
teeth are inclined to the axis of the wheel which helps in meshing more than
two teeth at a time.
1836- Worm gears are used when high velocity ratios required in a limited space
such as cream separator and hand chaff cutter.
1837- Miter gear is a special class of bevel gear where the shaft intersects at 90°
and the gear ratio is 1:1.
1838- Lubricants should be changed at least once in a year for proper functioning
of the tractor and transmission.

f) - Basic Civil Engineering:

1- Source and Classification of Stones:
1839- Rocks are made up of minerals. They can be monomineralic (single mineral)
or polymineralic (more than one mineral).
1840- The classifications of stones are physical (based on structure), chemical
(based on chemical composition), and practical (based on usage) and
geological (based on the mode of origin). Mineralogical classification is not a
means of classifying stones in general. It’s called chemical classification.
1841- Hot molten material is called Lava when it erupts from a volcano and reaches
the surface. Slag is waste material from the smelting of ore. Tuff is a porous
rock formed by a consolidation of volcanic ash.
1842- Plutonic rocks are formed by slow cooling of magma at considerable depth.
Volcanic rocks are formed near the surface of Earth by rapid cooling of
magma. Hypabyssal rocks are formed at a quick rate of cooling of magma at
considerably shallow depths.
1843- Weathered product remains at site is called residual deposit. Weathered
product carried away in solution is chemical deposit and weathered product
gets carried away agents is organic deposit.

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1844- Rocks are stable at a temperature below 200°C and at the pressure existing.
Any increase in above two factors can initiate the process of metamorphism.
One factor alone is not sufficient to start metamorphism.
1845- Silica predominates in siliceous rock and is less affected by weathering
and hence are hard and durable compared to argillaceous (clay), calcareous
(calcium carbonate) or carbonaceous (carbon).
1846- Foliated rocks can split up into layers along a definite direction only.
Sedimentary rocks are generally stratified and igneous rocks are unstratified.
1847- Granite is formed at a slow rate of cooling of magma at considerable depths
and so is a type of plutonic rock.
1848- Crushing strength or compressive strength of a stone is the load per unit area
at which the stone starts cracking. It should be greater than 100 N/mm2 to
ensure sufficient strength for use in construction.
1849- Granite and Quartz undergo sudden expansion and flies into splinters.
Limestone gets easily crumbled. Clay can withstand higher temperature and
is used in pizza ovens, fireplaces, etc…
1850- It’s required in structures subjected to heavy loading. Bridge is one such
structure. Slabs, walls and arches are not subjected to heavy loadings as a
bridge.
1851- A stone should be properly dried before using for structural works. The sap
contained in freshly quarried stones will make them soft and lead to decay
eventually.

2- Tests on Stones:
1852- Crushing test is used to find crushing strength of stones. Abrasion test to find
suitability of stone for road work. Acid test is used to find the quality of the
stone.
1853- As per the test procedure, the sample weighing about .5 – 1 N is placed in a
solution of HCl for 7 days.
1854- IS 1121 part 2 gives details about transverse strength, IS 1121 part 4 about
shear strength and IS 1126 about the durability of building stones.
1855- As per the IS codes, 40 × 40 × 40 mm size cube of stone is to be used to
perform the crushing test. The specimen is then placed in compression
testing machine (CTM) and loaded at 14 N/mm2.

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1856- Abrasion test is used to check compatibility of stone with other material by
allowing them to rub against each other, noting the wear resistance. Cast
iron balls of 48 mm diameter are placed in the apparatus along with the
specimen.
1857- Los Angeles is used for abrasion test, Deval’s for attrition and CTM for
compression or crushing test and Dorry’s apparatus is used to test the
hardness of stones.
1858- Mohr’s hardness scale ranks stones according to their hardness numbers.
Calcite has a hardness of 3, gypsum 2 and topaz 8.
1859- Crystallization of CaSO4 in pores causes decay of stones and the low solubility
in water prevent the use of this compound in the test.
1860- According to the IS code 2386, a 16 mm steel rod with rounded edge is used
for tamping the sample filled inside the cylinder in three layers, 25 times
each.
1861- Attrition test is performed to test the rate of wear of stones that are used in
road construction. It checks the rubbing against the same material of stone
and is expressed in percentage.
1862- Durability refers to the resistance of stones to atmospheric conditions such
as rain, heat, snow; temperature gradients; chemical impurities; cracks,
creeks.

3- Source and Classification of Sand:

1863- Sand is composed of small grains of silica (SiO2). It’s also called silicon dioxide.
1864- Pit sand doesn’t contain any salts and has sharp, angular grains. These are
the desired properties for a sand to be used for mortar and concrete.
1865- Pit sand is found in Earth in deposits. It is obtained by forming pits in the soil.
At a depth of 1 – 2 m from the ground surface, angular grained pit sand is
obtained.
1866- IS code 383-1970 gives the classification of sand based on the grading. There
are 4 grading zones. For each sieve size, there is a specific % of particle
passing through that sieve, denoted in the respective zone.
1867- River sand is constituted of fine round grains. These are the result of mutual
attrition under the effect of water current. It is naturally occurring, clean and
mostly white in color.

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1868- Sand size lies in the range 4.75 mm to 75 microns. A fine grained component
of a soil has a size less than 75 microns.
1869- There are three types of sands based on grain size distribution. They are fine
(passes through 1.5875 mm sieve), coarse (passes through 3.175 mm sieve)
and gravelly sand (passes through 7.62 mm sieve).
1870- Plastering is the act of applying a layer of plaster over a wall. It gives the wall
a smooth and decorative appearance. Hence, for achieving the smoothness,
fine grained sand is employed.

4- Bulking of Sand:
(Bulking of fine aggregate or sand is the phenomenon of increase
in sand volume due to the increase of moisture content.)
1871- When water is added to sand, a thin film of water is formed around the sand
particles. The film exerts surface tension on particles, making them move
apart. This leads to an increase in volume because there is no direct contact
among particles.
1872- The volume i.e. bulking increases as sand absorbs moisture. At about 6- 10%,
the film starts breaking and the volume reduces. If sand absorbs further
moisture, no bulking takes place.
1873- As fine grained sands have higher voids than medium and coarse grained
sands, the percentage of moisture absorbed and the percentage volume
increase is the highest.
1874- Finer particle size will have more voids compared to coarser once. They tend
to absorb more water and hence exhibit more bulking.
1875- A completely saturated sand has no void space left to absorb any more water
and undergo bulking.
1876- The excess water in the sand can be used to maintain water-cement ratio. It
improves workability and hence it is easier to place fresh concrete. Strength
is a property of hardened concrete.

5- Properties of Sand:
1877- Fineness modulus is an index number which represents average size of sand
particles. It is calculated after conducting sieve analysis.
1878- The fineness modulus of sand lies in the range 2-3.
1879- For sand to be used in every type of construction, the grains must suit all
requirements. Angular, coarse grained sand is the one suitable for all work.

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1880- The grade and amount of sand used in making mortar help in adjusting the strength
parameter. It also helps in increasing resistance against crushing.
1881- An ideal sand should be hard and not soft. It will be difficult to work with if it is soft.
1882- The particle size of sand is between 4.75mm and 75 microns.
1883- Bulking increases volume of mortar and not the strength. In fact, it decreases the
strength, leading to future cracks in the structure.
1884- A small amount of sand is added to a solution of sodium hydroxide and stirred. If
color changes to brown, presence of impurity is detected.
1885- If more silt content is present, it will lead to the improper measurement of volume
or weight. It should be washed off to bring it to the allowable limit.
1886- 1682 kg/m3 is density of rammed sand, 1281 kg/m3 is density of dry sand and 1522
kg/m3 is of silica sand.

6- Properties of Cement:
1887- Natural cement sets very quickly after the addition of water and hence it is
not quite workable. Artificial cement is preferred over this.
1888- Joseph Aspdin patented Portland cement in 1824. William Aspdin, his son is
regarded as the inventor of modern Portland cement due to his
developments in 1840s.
1889- Approximately 95% of cement particles are smaller than 45 microns and the
average particle size is 15 microns.
1890- When cement paste hardens and sets, it should not undergo any volume
change. Soundness ensures this and is tested using Autoclave expansion test.
1891- The color of cement is normally grey with a greenish tint. There are different
shades – lighter and darker, but it does not go as dark as blackish grey.
1892- Core cutter is used to determine dry density of soil. Vibrator is used in sieve
analysis. UTM can be used to test various parameters – tension, bending, and
shear of various materials. Vicat apparatus consists of a needle, used to
penetrate the cement paste sample.
1893- As per IS code 4031-part 5, the initial setting time of cement is minimum of
30 minutes. After this cement will start losing its plasticity and will not be
workable.
1894- For coarser particles, hydration starts on the surface of particles, hence, it
might not be completely hydrated. This causes low strength and low
durability.

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1895- Cement is highly alkaline and setting process is exothermic. Wet cement is
strongly caustic and causes skin burns. Similarly, dry cement causes eye or
respiratory irritation, when it comes in contact with mucous membranes.
1896- Cement contains about 60-65% of lime. Silica constitutes 17-25%, alumina 3-
8% and magnesia 1-3%.
1897- Presence of lime in sufficient quantity is necessary to form silicates and
aluminates of calcium. Excess lime leads to expansion, disintegration and
unsoundness of cement.
1898- Calcium sulphate is found in cement in the form of gypsum. Its slows down
the setting time of cement.
1899- Aluminium Oxide or Alumina is present in small quantity in cement and it
helps in a quick-setting property.
1900- There are 8 main ingredients present in cement. They are lime, silica,
alumina, magnesia, iron oxide, calcium sulphate, sulphur trioxide and alkalis.
1901- Excess of magnesium causes problems in structures built with this cement. It
causes cracks in both mortar and concrete after they harden.
1902- Cement blocks are prepared to test their compressive strength. With proper
curing and attaining strength, these can be tested. It requires 28 days to fully
cure and attain the strength of required grade, say 43 N/mm2 for grade 43
OPC.
1903- Cement blocks can be tested at 1 day, 3 days, 7 days and 28 days. Usually 1
day doesn’t give any result. Strength of 43 grade OPC at the end of 3 days is
23, 7 days is 33 and 28 days is 43. So, it increases with time.
1904- Cement stored in the factory of more than 6 months has to be retested and
rejected if it does not meet requirements. Time period of more than 3
months is for cement bags with vendors.

7- Composition of Good Brick Earth:

1905- For a good brick earth, 5 major constituents are needed. They are alumina,
silica, lime, oxides of iron and magnesia.
1906- The amount of silica present in brick earth is 50-60% and it prevents cracking
and warping of raw bricks.
1907- Iron oxide imparts the red color to the brick. Presence of magnesia makes
brick yellowish and manganese makes it black. Excess of oxides of iron makes
the brick dark blue on burning.

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1908- Raw bricks develop shrinkage, cracks, warping in presence of excess alumina.
Other three changes happen on burnt bricks or final brick product due to
excess of other constituents.
1909- Alkali exists in the form of soda and potash. Alkalis absorb moisture and with
a passage of time, it gets evaporated, leaving white powdery deposits called
efflorescence.
1910- Silica is present is either free or combined form. It is usually present as sand,
which is cohesionless in nature. So, excess of silica would lead to loss of
cohesion between particles and this make the brick brittle.
1911- Organic matter aids in the burning process. If it does not get burnt
completely, gases are released which will lead to the formation of small
pores, making brick porous.
1912- The three types are loamy, mild or sandy clay; marls, chalky or calcareous
clay and plastic, strong or pure clay.

8- Tests on Bricks:
1913- The sample brick is oven dried, cooled and then soaked in water at room
temperature for 24 hours.
1914- As per IS codes, the loading on brick specimen in a CTM should be uniform
at rate of 14 N/mm2 per minute.
1915- Brick is scratched using finger nail. If there are no visible scratches made on
the brick surface, it is said to be sufficiently hard.
1916- It is a test for soundness of brick. A sound brick should not break. It should
produce a clear ringing sound. A dull sound indicates an unsound brick.

9- Classification of Timber:
1917- The life time of high durability timber is more than 10 years, for moderately
it is between 5-10 years and for low, it is less than 5 years.
1918- Sal, Oak and Mahogany are all examples of hard wood.
1919- Density of light to very light timber is less than 5.5 kN/m3. Moderate timber
has density between 5.5 and 7.5 kN/m3 and heavy to very heavy timber has
density greater than 7.5 kN/m3.
1920- The other 3 options are properties of hard wood. Soft wood is light in color,
annual rings are clearly visible and it has resinous structure.

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10- Seasoning of Timber:

(Seasoning is the process of drying timber to remove the bound
moisture contained in walls of the wood cells to produce seasoned
timber. Seasoning can be achieved in a number of ways, but the aim
is to remove water at a uniform rate through the piece to prevent
damage to the wood during drying (seasoning degrade).
1921- Tree when felled contains sap and high moisture content. To use it for
engineering purpose, it has to be dried. The process of drying timber to
remove water is called seasoning.
1922- Seasoning increases the stiffness of timber. It takes away sap and moisture
content and imparts stiffness to timber.
1923- Natural seasoning is the one that gives stronger timber. Kiln seasoning
results in weaker, lighter timber.
1924- Natural seasoning is a very slow process, as timber is stacked and blowing
natural wind seasons it. It may take anywhere from 1-4 years for obtaining
properly seasoned timber.
1925- Air or natural seasoning does not require power, skilled supervision and
elaborate equipment. These are all advantage of air seasoning. It might not
give uniformly seasoned timber.
1926- The 5 types are water seasoning, boiling, chemical seasoning, electrical
seasoning and kiln seasoning.
1927- Timber pieces are totally immersed in running water for 2-4 weeks. The sap,
organic matter is carried away by water in water seasoning. It renders the
timber brittle.
1928- Electric seasoning involves passing high electricity through timber. Since it is
a bad conductor of electricity, it gets heated up. It results in rapid seasoning
and it is effective as it provides uniform seasoning.
1929- Timber is immersed in water and allowed to boil for 3-4 hours. Then it is
taken into shed and dried very slowly.

11- Market Forms and Uses of Steel:

1930- Cast iron contains 2-4% of carbon, wrought iron contains less than 0.15% of
carbon and stainless steel contains maximum 0.08% carbon.
1931- Mild steel contains carbon up to 0.25%. Medium carbon steel has 0.25%-
0.7% carbon. Hard steel has 0.7-1.5%.

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1932- Since it has very low carbon contents that is 0.05-0.1% it can be used for low
strength works.
1933- Concrete and steel are primarily used in R.C.C – reinforced cement concrete.
Concrete is strong in compression and weak in tension. Steel is strong in both
properties and hence provides strength to the structure.

12- Sieve Analysis:

1934- According to IS 565, the sieve sets are 80mm, 40mm, 20mm, 10mm, and
4.75mm for coarse aggregates.
1935- At the base of all the sieve sets, round pan is placed to collect the particles
finer than the last sieve size. It is called the receiver.
1936- The percentage retained is calculated by dividing weight of sample retained
by the weight of the total sample, taken in beginning of test.
1937- A graph is plotted after performing sieve analysis. It shows different curves.
A narrow gradation is also called uniform gradation. It shows that the
aggregate is of approximately the same size.
1938- As per IS code 2720 Part 4. Mechanical vibrator is switched on and allowed
to vibrate for 15-20 minutes. It ensures proper grading of particles.
1939- IS 2720 gives the specifications. It requires using sample weighing 5 kg for
coarse aggregates and 1 kg for fine aggregates.

13- Composition of Concrete:

1940- Concrete is prepared by mixing cement, fine aggregate, coarse aggregate
with water. It is a thick paste and hence has high bulk density.
1941- Asphalt is the highly cementitious material. It possesses almost all qualities
of cement and is widely used as an alternative to cement.
1942- Ideal water cement ratio for general works is 0.45. During machine mixing, it
can be in the range of 0.4-0.5. Hand mixing is done by laborers and maximum
0.6 can be allowed.
1943- Admixtures are compounds added to concrete to attain specific properties.
The chemical admixtures are added in small amounts. The 4 types are
accelerators, retarders, plasticizers and air entraining agents.
1944- More water improves the workability of a mix, but compromises on the
strength requirements. Hence, ideal w/c ratio of 0.45 is to be used.

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1945- Aggregates used are sand, gravel or crushed stones. These have high
compressive strength. Concrete is strong in compression and weak in tension
due to this reason.
1946- Concrete is graded into many types as per IS 456-2000. M stands for mix and
the number, say, 20 is a compressive strength after 28 days in N/mm2.
Generally, M20 grade is used. The ratio of cement: fine: coarse aggregate for
M20 is 1:1.5:3. For M10 it is 1:3:6, M15 it is 1:2:4 and M25 it is 1:1:2.

14- Basic Surveying Terms:

1947- Bench mark is an object bearing a marked point whose elevation above or
below a datum is known. The 2 types are the temporary and permanent
bench mark.
1948- Declination is determined using the compass. The error is calculated and the
necessary addition or deduction is carried out.
1949- Well-conditioned triangles are those triangles with an angle less than or
equal to 60o. The plot is divided into such triangles, as it is the easiest figure
that can be plotted and analyzed.
1950- If a stone is used to mark a boundary, it is called Merestone. If a tree is on
the property line, it is called a Line tree.
1951- Based on place of survey, the classification includes land, marine and
astronomical categories. Basement refers to underground, no survey is
performed there.
1952- Based on Earth’s curvature to be considered or not while surveying, plane
and geodetic surveying are there. Earth’s curvature is considered in geodetic
and not considered in plane surveying.
1953- Those errors which are made while performing survey are called gross errors.
These can accumulate and finally lead to re-doing the whole procedure.
Systematic error follows a consistent pattern.
1954- Theodolite is an instrument used to measure angular readings. It is used in
angular surveying. All other options are used to take linear measurements.
1955- An acre is equal to 43,560 square feet. A hectare is equal to 2.471 acres or
107,639 square feet.

15- Chain Surveying:

1956- Offsets are taken perpendicular to the survey lines. They are used to mark
objects and the lateral distance to them, using an offset rod.

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1957- There is no instrument like an optical staff. Optical Square is an instrument
which consists of circular box with three slits. Cross staff is a frame of the box
mounted on a pole. Prism square is an advanced version of an optical square.
Site square consists of two telescopes set at 90os.
1958- There can be 5 types of chains used for chain surveying. They are the metric
chain, Gunter’s chain, engineer’s chain, revenue chain and steel band or
band chain.
1959- Gunter’s chain is also called surveyor’s chain and is 66ft long. It consists of
100 links, each being 0.6 ft. Eighty Gunter’s chain corresponds to 1 mile.
1960- Ranging is used to locate intermediate points. They are marked using ranging
rods. It is done when a survey line is very long and marks are required to
distinguish the line.
1961- The line joining the main survey station is called the main survey line. The
biggest of the main survey line is the base line, and other features are plotted
with respect to this line.
1962- Chain surveying is suitable for a survey of small areas. The area is divided into
well- conditioned triangles and triangulation is the principle used.
1963- Ranging is of 2 types – direct and indirect. Direct ranging is done using a line
ranger or naked eye. Indirect ranging is done when starting and ending
points are not visible.
1964- Field book is used to enter all the measurements done while surveying. It is
an oblong book of size 20x12cm and opens length wise.
1965- The three types are open cross staff, French cross staff and adjustable cross
staff. Open cross staff has two vertical, opposite slits. French cross staff
consists of a hollow octagonal box. The adjustable cross staff consists of two
cylinders of equal diameter, one placed on top of the other.
1966- Bearing of the line gives its direction relative to a given meridian. It can be
measured as an angle using any angular measuring instruments.
1967- The two compass types used in surveying are Prismatic Compass and
Surveyor’s Compass. Prismatic Compass is most commonly used one for
surveying.
1968- Fore bearing is used to indicate the angle measured in the direction of
progress of the survey. The angle measured in the opposite direction of
progress of the survey is called back bearing.

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1969- In reduced bearing system bearing is measured from the nearest one, North
or South is anticlockwise or clockwise direction. It aims at locating nearest
bearing.
1970- Prismatic Compass functions based on WCB – whole circle bearing and
surveyor’s compass functions based on the reduced bearing system.
1971- True, magnetic and arbitrary meridians are used. True meridian passes
through true North and South. Magnetic meridian passes through magnetic
North and South. Arbitrary meridian is used for rough purposes.
1972- While reading a compass, sometimes needle might be slightly deviated from
magnetic North. It can be due to any weather conditions, magnetic objects
nearby. It has to be corrected to get accurate readings.
1973- Isogonic line passes through points of the same declination. Agonic line
passes through points of zero declination. Other options are invalid.
1974- In a prismatic compass, the sight vanes are generally not adjustable. In
surveyor’s compass, it’s one of the permanent adjustments done.

16- Plane Table Surveying:

1975- There are four ways to perform plane table surveying. They are radiation,
inter-section, traversing and resection. First two are employed for locating
details and other two for locating plane table stations.
1976- In the graphical method of surveying, objects are sighted and taken down as
drawings (lines) on a paper. The line gives angle, distance of the object from
the station.
1977- Plane table is a well-seasoned wooden piece. It is polished and a smooth
surface is given on top. The middle bottom portion is threaded to attach a
tripod.
1978- It is used only to locate a certain local object. It doesn’t give accurate results
and can’t be used for high precision works.
1979- Orientation refers to the process of keeping the table to the position which
is occupied at first station. The point on paper and ground should match. It
can be done by using through compass and back sighting.
1980- Traversing is a methodology where the number of connected lines are there
whose length is measured using tape/chain and angle using any angle
measuring instrument. PT survey uses this methodology.

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1981- Plumbing fork is also called U-fame. It has a U-shaped frame which can be
clamped onto the plane table. The lower end has provision for suspending a
plumb bob. It is used to center the table w.r.t station.
1982- Only one linear measurement is made in the intersection method. Base line
is the line showing distance between two instrument stations. This method
is also called graphical triangulation.
1983- There are four methods to perform the resection. They are using a compass,
by back sighting, solving two-point and three-point problem. There is no
method as solving four point problem.

17- Equipment Used in Levelling:

1984- There are 4 chief types of levels used. They are Dumpy level, Wye Level,
Reversible level and Tilting level.
1985- A levelling staff is a straight rectangular rod, with graduations, zero starting
from foot of staff. It is placed at the required point and horizontal line of sight
from a level is made.
1986- There are 2 categories – self reading staff and target staff. Self-reading staff
can be directly read from the instrument through the telescope. Target staff
consists of moving target against which reading is to be taken.
1987- There is a tube and bubble is enclosed in it. Using 3 foot screws, the bubble
is centralized. Once it is stable, the level is said to have maintained a
horizontal line of sight.
1988- Digital level is an electronic level. It is set up on a tripod and it reads a
barcoded staff. All the details are fed into the memory of level and can be
retrieved on a computer.
1989- There are 3 types of self-reading staff. They are solid, folding and telescopic
staff.
1990- Tilting screw is found only in the tilting level. Using this, one can tilt the
telescope to the required angle, keeping the vertical axis.
1991- Level vials contain a bubble, which is to be centralized to obtain a horizontal
line of sight. It may be of bulls-eye type (circular shaped) or vial type (tube
shaped).
1992- Compensator is also called stabilizer. It consists of 2 fixed prisms and it
creates an optical path between eye piece and objective. It results in exact
positioning of the line of sight due to gravity.

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18- Methods of Levelling:

1993- The 2 methods are the height of instrument method and rise and fall
method. These are used to evaluate heights of various points.
1994- There are 4 ways to perform levelling. They are direct levelling, trigonometric
levelling, barometric levelling and stadia levelling.
1995- In trigonometric levelling, the horizontal distance and vertical angle are
measured from the station to the object. It uses trigonometric relations to
compute the vertical height of a point.
1996- In differential levelling, a number of inter-stations are located and then the
instrument is shifted to each station and the elevation is observed.
1997- Fore sight (FS) is noted as last reading and back sight (BS) is noted as first
reading taken from the instrument. Any intermediate points are noted down
as intermediate sight (IS).
1998- Reciprocal levelling is used when Obstacles are there.
1999- Explanation: If the points to surveyed lie on opposite banks of a river,
reciprocal levelling can be used. It is done from both sides to eliminate
chances of error.
19- Environmental Engineering:
2000- The biosphere consists of 3 components – land (lithosphere), water
(hydrosphere) and air (atmosphere). They are all necessary for life to sustain
on earth.
2001- Water may be polluted by the presence of some unpleasant gases from
industries. They are recognized by the foaming of water.
2002- The rejected materials which are collected in dustbins and the foul
discharges that are carried by underground drains are termed as refuse. It
may be dry refuse (grass, paper, cloth, vegetable peels) or wet refuse
(urinals, kitchen discharges).
2003- Trenching is a method of disposing of solid waste. Trench is dug of size 12 x
3 x 2m, waste is filled and levelled and then covered with a layer of earth or
ash.
2004- Coagulation can be explained by this method. Floc is the thick gelatinous
precipitate which forms when chemicals (coagulants) are mixed with water.
2005- Use of excess fertilizers destroys the microbial plant life in the soil. It leads
to disturbance of nitrogen fixation, which is an essential process in soil.

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2006- Hypoxic zones are also called dead zones. These are areas with low oxygen
content and can be inhabitable for living organisms. Any failure in the
hydrosphere within oxygen cycle can lead to the formation of hypoxic zones.

20- Wastewater Management:

2007- The domestic wastewater generated from household laundry, preparation
of food, cleaning of utensils and personal washing is called sullage.
2008- In conditions of warm weather, the dissolved oxygen content of the
wastewater loses and it becomes septic. It has an offensive odour of
hydrogen sulphide.
2009- The extent of treatment depends on 2 factors- the quality of water (depends
on the source) and the beneficial uses (high quality for domestic, production
sector, low quality for housekeeping, a germ free for recreational and for
agricultural purposes having low TDS, Na ratio, etc.).
2010- Turbidity is the presence of solid particles in water. The removal of it
removes the colour, taste, odour producing components and makes water
pleasant and safe to drink.
2011- Chemicals like alum and lime are added to the raw water. Then a rapid mix
is done to mix the chemicals with the water. After this, it goes into the
coagulation unit, where the colloidal particles combine to form a flock.
2012- Disinfection is the most inexpensive way of killing the microorganisms
present in the water. The water is chlorinated and some residual chlorine of
0.5mg/litre is left so that contamination in the distribution system is taken
care of.
2013- The seven factors are ground conditions, ground water level, location and
type of water source, topography, quantity and quality of wastewater
produced, climatic, socio-cultural factors.

21- Solid Waste Management:

2014- There are broadly 9 sources of solid waste. They are residential, industrial,
commercial, institutional, construction & demolition areas, municipal
services, treatment plants, agriculture and biomedical.
2015- The generation of solid waste cannot be stopped. The idea behind solid
waste management is to reduce and eliminate the adverse effects of these
on the environment and human health.

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2016- The six functional components in order are waste generation (identification
of waste), onsite handling & storage (at site of waste), waste collection
(collecting from different sources), waste transfer (local to regional site),
waste processing (sorting of reusable/recyclable) and disposal (at
landfills/waste to energy).
2017- The average composition of Municipal solid waste is 41% organic, 40% inert
& 19% recyclable.
2018- The bulk of organic waste arrives from households and agriculture. The inert
waste is generated from construction sites, demolitions, public places, etc.
2019- The process which use heat to treat the waste are referred to as a thermal
treatment. These include incineration (combustion of waste & recover
energy for electricity/heating), pyrolysis (decomposition of organic waste
with low oxygen and high temperature), and open burning (environmentally
harmful and mostly practical).
2020- They are sanitary landfills, controlled dumps and bioreactor landfills.
Sanitary landfills are the most common and are situated where the land
features aid in decomposition. Controlled dumps are well planned sites and
bioreactor landfills use a superior microbiological process for decomposition.
2021- The thermal process uses heat in varying temperatures to disinfect the
pathogens present. Autoclave & microwave process uses low heat whereas
incinerator and hydroclaring use high heat to render the waste pathogen
free.
2022- The WHO has classified the bio-medical waste into 4 categories- infectious
(waste from surgeries and any material containing pathogens), pathological
(tissues/organs/drugs, etc which are not required), radioactive
(contaminated with a radioactive substance) and others (waste from hospital
housekeeping/kitchen).
2023- Methane is released by the decomposition under anaerobic conditions. This
can cause fires and explosions and promote global warming too.

22- Sustainable Engineering:

2024- Carbon footprint is the total set of greenhouse gas emissions caused by an
individual, event, organisation or product. It is expressed as carbon dioxide
equivalent. It can be measured by assessment of GHG (greenhouse gas)
levels or activities like carbon accounting.

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2025- Ecological pyramid is a graphical representation used to show bio
productivity at each trophic level. The three types are the pyramid of energy,
pyramid of numbers and pyramid of biomass.
2026- Agenda 21 is a comprehensive blueprint of action to be taken globally,
nationally and locally by governments of member nations of UN and those
major groups in every area in which humans impact on the environment.
2027- Hydel power is obtained from a high velocity of running water. It is
abundantly present. It is used for a longer period of time. It is an exceptional
case of conventional energy.
2028- These are three scales of environmental issues – local, regional and global.
Climate change, global warming, stratospheric ozone less, etc. are all issues
at a global level.
2029- It is stored in the roots of trees and organic matter for decades in the form
of biomass. The carbon from these are released into the atmosphere on
decomposition.

23- Biodiversity and Ecology:

2030- The three types are species diversity (number of the different species found
in location), Genetic diversity (genetic variations within a species) and
Ecological diversity (variations in the ecosystems of regions).
2031- Biodiversity helps in maintaining ecological stability. The ecosystems have an
ability to maintain its original nature even after disturbances occur within it,
with the help of biodiversity.
2032- The ever-exploding increase in human population leads to the consumption
of resources and exploitation of the earth’s surface. This results in the
destruction of natural habitats and ecosystems. The use of sustainable
alternatives is a step towards conservation.
2033- The conservation methods are broadly classified as in-situ conservation (the
species are conserved in their natural ecosystems, which are protected) and
ex-situ conservation (breeding of new and endangered plants/animals in
controlled conditions).
2034- Sanctuaries are the areas where only wildlife is present. So, cultivation,
harvesting of timber, etc is permitted only if does not interfere with the
project.

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24- Geotechnical Engineering:

2035- In Geotechnical Engineering, water content is an important parameter for
analysing the soil. It is expressed as mass of water divided by mass of solids.
It is denoted by w and expressed in %.
2036- Darcy’s Law states that the rate of flow per unit time is proportional to a
hydraulic gradient. q∞iA is the mathematical representation of the law.
2037- There are 4 methods available to measure shear strength of soil – direct
shear, triaxial compression, unconfined compression and vane shear test.
Triaxial compression test is the most accurate one.
2038- On compaction of a soil mass, the shear strength is increased. It is tightly and
firmly compacted and offers resistance to deformation and flow.
2039- Soil is a 3 phase material. It consists of solids, water and air voids. It is
represented in a 3 phase diagram with volume on left side and mass on the
right side.
2040- Fine particles should pass through 75μ IS sieve. Fine particles include clay,
silt and organic content in a soil mass.
2041- Mass density is the ratio of mass of water to volume of water. At 4oC, it is
1g/ml or 1000kg/m3 or 1Mg/m3.
2042- Percentage air voids is the ratio of volume of air in voids to total volume of
soil. It is denoted by naand expressed as a %.

25- Soil Properties:

2043- Particle density is mass per unit volume of soil particles. It is expressed in
g/cc and most soils have 2.6 g/cc as particle density.
2044- Soil can exist in four states based on the amount of water content. They are
liquid, plastic, semi solid and solid state. Water content decreases with each
state.
2045- An optimum and constant temperature of 105-110oC is to be maintained in
the oven. The specimen is kept for about 24 hours to ensure proper drying.
2046- The mineral components of soil are termed as separates. These are three of
them – clay, silt and sand. Various soils are designated based on the
proportion of separates.
2047- Relative density is used to express relative compactness of cohesionless soil.
It ranges from <10 to 100 (very loose to very dense). Loose soil has a relative
density between 10 and 35.

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2048- The water content at which soil changes from liquid to plastic state is liquid
limit. Casagrande apparatus consists of a rubber base and brass cup. Sample
is filled in a cup, subjected to blows by rotating handle at 2 revolutions per
second. Water content corresponding to 25 blows is the liquid limit.
2049- The two tests are constant head permeability test and variable head
permeability test. The constant head permeability test is done for highly
permeable soil and the other one for fine grained soil.
2050- The five types are macropore (too large, >75μm), mesopore (30-75μm),
micropore (5-30μm), ultramicropore (0.1-30μm) and cryptopore (smallest, <
0.1 μm).
2051- Based on the degree of distinctness of peds (natural aggregates of soil
particles), there are 4 grades of soil. They are structureless, weak, moderate
and strong.

g) - IC Engine:
1- Engine Performance Parameters:
2052- Relative efficiency is defined as the ratio of indicated thermal efficiency to
the corresponding air standard cycle efficiency.
2053- The air standard efficiency of an Otto cycle compared to a diesel cycle for
the given compression ratio is more.
2054- The calorific value of gaseous fuels is expressed in terms of Kcal/m3.
2055- Indicated power of a 4-stroke engine is equal to pLAN/2.
where p = mean effective pressure,
L = stroke
A = area of piston and
N = rpm of engine.
2056- If the intake air temperature of I.C. engine increases its efficiency
will decrease.

2- Air Standard Cycles:

2057- The air standard efficiency of an I.C. engine depends on compression ratio.
2058- Generally, the specific fuel consumption per B.P. hour for a petrol engine is
about 0.25 kg while the specific fuel consumption per B.P. hour for a diesel
engine is about 0.2 kg.

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2059- The compression ratio in I.C. engine is directly proportional to the thermal
efficiency, so as it increases, then its thermal efficiency will increase.
2060- The working medium of an air standard cycle has constant specific heat
throughout the cycle.
2061- It is assumed that all the processes of an air standard cycle are reversible.

3- Carnot Cycle:
(The Carnot cycle is a theoretical ideal thermodynamic cycle proposed
by French physicist Nicolas Léonard Sadi Carnot in 1824 and expanded
upon by others over the next few decades……an ideal reversible closed
thermodynamic cycle in which the working substance goes through the
four successive operations of isothermal expansion to a desired point,
adiabatic expansion to a desired point, isothermal compression, and
adiabatic compression back to its initial state.)
2062- In a Carnot cycle the working medium receives heat at a higher
temperature and rejects heat at a lower temperature.
2063- As Carnot cycle is an ideal cycle, so the working fluid is an ideal gas.
2064- The isothermal process of a Carnot cycle needs very slow motion of the
piston to maintain constant temperature while the adiabatic process needs
very fast motion to complete the adiabatic process.

4- Otto Cycle:
(An Otto cycle is an idealized thermodynamic cycle that describes the
functioning of a typical spark ignition piston engine. It is the
thermodynamic cycle most commonly found in automobile
engines….The Otto Cycle, describes how heat engines turn gasoline into
motion. Like other thermodynamic cycles, this cycle turns chemical
energy into thermal energy and then into motion. The Otto
cycle describes how internal combustion engines (that use
gasoline) work, like automobiles and lawn mowers.)
2065- The efficiency of an Otto cycle is increased by increasing compression ratio.
2066- The thermal efficiency of theoretical Otto cycle does not depends upon the
pressure ratio,
2067- The work output of the theoretical Otto cycle is increases with increase in
compression & pressure ratio.

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2068- The mean effective pressure of an Otto Cycle is directly proportional to its
compression ratio, so it increases with an increase in compression ratio.
2069- In Otto cycle, heat addition takes place at constant volume.

5- Diesel Cycle:
(The Diesel cycle is a combustion process of a reciprocating internal
combustion engine. In it, fuel is ignited by heat generated during the
compression of air in the combustion chamber, into which fuel is then
injected.)
2070- Diesel cycle is also known as constant pressure cycle as pressure is constant
in this cycle.
2071- The combustion in compression ignition engine is heterogeneous.
2072- In a diesel engine, the fuel is ignited by heat resulting from compressing air
that is supplied for combustion.
2073- The thermal efficiency of a diesel cycle having fixed compression ratio, with
increase in cut-off ratio will decrease.
2074- The pressure at the end of compression, in diesel engines, is approximately
35 bar.
2075- The combustion in spark ignition engine is homogeneous while the
combustion in compression ignition engine is heterogeneous.
2076- If the temperature of intake air in I.C. engine is lowered, then its efficiency
will increase.
2077- The fuel in diesel engine is normally injected at pressure of 90-130 kg/cm2.

6- Dual Cycle:
2078- Dual Cycle is a combination of Otto cycle and Diesel cycle.
2079- Another name for Dual cycle is a mixed cycle.
2080- Since, Dual Cycle is a combination of Otto cycle and Diesel cycle, so in Dual
cycle, generally heat addition takes place first at constant volume then at
constant pressure.
2081- Since, Dual Cycle is a combination of Otto cycle and Diesel cycle, so in Dual
cycle, generally heat rejection takes place at constant volume.
2082- Most high speed compression engines operate on Dual cycle.

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7- Fuel Air Cycle:

2083- The air fuel ratio of the petrol engine is controlled by carburettor and not by
injector or fuel pump.
2084- The theoretically correct air fuel ratio for petrol engine is of the order of 15:1.
2085- Air fuel ratio at which a petrol engine cannot work is 20:1 and less.
2086- For maximum power generation, the air fuel ratio for a petrol engine of
vehicles, is of the order of 12:1.
2087- 9-10m3 volume of air is required for consuming 1 liter of fuel by a four stroke
engine.

8- Fuels:
2088- Ignition quality of petrol is expressed by octane number and that of diesel by
cetane number.
2089- Petrol is distilled at a temperature in range of 65-220ºC while kerosene is
distilled at 220-350ºC.
2090- Iso-octane has an octane number of 100.
2091- Cetane is a straight chain paraffin.
2092- Gasoline is the lightest and most volatile liquid fuel.
2093- Polymerization is defined as a chemical process in which molecules of a
compound become larger.
2094- In a diesel engine the diesel fuel injected into cylinder would burn instantly
at about compressed air temperature of 1000ºC.
2095- The rating of a diesel engine, with an increase in air inlet temperature, will
decrease linearly.
2096- The knock in diesel engine occurs due to instantaneous and rapid burning of
the first part of the charge.
2097- Violent sound pulsations within the cylinder of an I.C. engine are caused due
to detonation.
2098- Auto-ignition temperature is defined as that temperature at which it catches
fire without external aid while volatility of diesel fuel is indicated by 90%
distillation temperature.
2099- The delay period in petrol engine is of the order of 0.002 sec.
2100- A fuel will detonate less if it has higher self-ignition temperature.
2101- Ignition quality of diesel fuel oil is expressed by an index called cetane
number.

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2102- Calorific value of diesel oil is of the order of 10000 kcal/kg.
2103- Carbon residue in diesel oil should not be more than 0.1%.
2104- The specific gravity of diesel oil is 0.85.
2105- The efficiency of I.C. engines normally is of the order of 30-35%.
2106- The firing order of a six stroke I.C. engine is 1-5-3-4-2-6 and the firing order
in the case of four cylinder in-line I.C. engine is 1-3-4-2.
2107- Sulphur content in diesel engine oil should not be more than 1%.
2108- The ash content in diesel oil should not be more than 0.01% while sulphur
content in diesel engine oil should not be more than 1%.
2109- Paraffins are generally represented by CnH2n+2 while olefins are generally
represented by CnHn .
2110- Olefins are represented by CnHn and paraffins are generally represented by
CnH2n+2.
2111- Hydrocarbons are decomposed into smaller hydrocarbons by cracking while
the molecular structure of the straight-run gasoline is changed by reforming.
2112- The molecular structure of the straight-run gasoline is changed by reforming
and hydrocarbons are decomposed into smaller hydrocarbons by cracking.
2113- For S.I. engines fuel most preferred are aromatics while for C.I. engines fuel
most preferred are paraffins.
2114- Detonation in petrol engines can be suppressed or reduced by the addition
of small quantity of lead nitrate.
2115- As compared to other fuels there is almost no delay in gaseous fuel and for
this purpose, it is preferred the most.
2116- The main advantage of hydrogen as an IC engine fuel is that there are no HC
and CO emissions.
2117- Only methane is the major constituent of natural gas.
2118- The octane number of natural gas is always > 100.

9- Carburetion:
2119- The purpose of the carburetor is to supply petrol and air.
2120- The compensating jet in a carburetor supplies an almost constant amount of
petrol at all speeds because the flow is produced due to the static head in
the float chamber.
2121- Fuel injector is not related to spark ignition engine as there is no fuel injection
in spark ignition engine.

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2122- In carburetors, the top of the fuel jet with reference to the level in the float
chamber is kept at slightly higher level.
2123- The purpose of carburetion is to break up and mix the petrol with air.
2124- Power impulses from IC engine are smoothed out by flywheel as the energy
is stored in the flywheel.
2125- Concentric type of carburetor is preferred as it gives a better fuel ratio.
2126- A simple carburetor supplies a rich mixture during accelerating.
2127- The size of the carburetor is generally given in terms of the diameter of the
venturi tube in mm.
2128- Venturi tube is also known as throat.
2129- Carburetor depression is defined as the pressure difference between the
float chamber and the throat of the venturi.
2130- Modern carburettors provide the correct quality of air-fuel mixture during all
the conditions of starting, idling and cruising.
2131- The air fuel ratio of the petrol engine is controlled by carburetor while the
injector is used to inject fuel and governor is inside engine.
2132- To prevent blockage of the nozzle by dust particles, the gasoline is filtered by
installing a fuel strainer at the inlet to the float chamber.
2133- The function of a float chamber in a carburetor is to supply the fuel to the
nozzle at a constant pressure head and not at constant volume or variable
pressure.
2134- Generally, carburetors are categorized depending upon the direction of flow
of air and not on fuel flow.
2135- Generally, in updraught type carburetors, air enters at the bottom and leaves
at the top.
2136- Generally, in updraught type carburetors, air leaves at the top and enters at
the bottom.
2137- Generally, in the constant choke carburetor, the air and fuel flow areas are
always maintained to be constant.
2138- In constant vacuum carburetor, the vacuum is maintained at a constant rate
while air and fuel are maintained at a variable rate.

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10- Injection Systems:

2139- In a fuel-injection system, the amount of fuel delivered into the air stream
going to the engine is controlled by a pump which forces the fuel under
pressure.
2140- In an air injection system, generally fuel is forced into the cylinder by means
of compressed air.
2141- Fuel injector is used for CI engines and not for SI engine and gas engines.
2142- Fuel injection pressure in solid injection system is around 200-250 bar.
2143- Generally paper is not used as fuel filters.
2144- The methods used on fuel injection are air injection, mechanical injection
and solid fuel injection.
2145- Generally, the removal of air from the pipeline is termed as bleeding in
injection system.
2146- The types of diesel injectors are single hole injector, multi hole injector and
long stem injector.
2147- In pre-chamber and swirl type of combustion system pintle nozzle is used
and not the other nozzles.
2148- Generally, intaux nozzle is used to enable cold starting, without the use of a
heater plug.
2149- Generally, solid injection is also called mechanical injection.
2150- Fuel is injected into the cylinder at the end of the compression stroke and
not at suction or expansion stroke.

11- Injection Pump:

2151- The jerk type injection pump consists of a reciprocating plunger inside a
barrel and not a distributer.
2152- Generally, the plunger of a jerk type pump is driven by a camshaft.
2153- The axial distance traversed by the plunger is constant and hence same for
every stroke.
2154- In a distributer type of injection pump, the fuel is distributed to each cylinder
by means of a rotor while in a jerk type plunger is used.

12- Injection Pump Governor:

2155- Rate of fuel injection is directly proportional to engine speed, so fuel
delivered by a pump increases with speed.

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UNIVERSITY RAWALPINDI)
2156- Quantity of fuel delivered increases with load causing excessive carbon
deposits and high exhaust temperature.
2157- The purpose of a governor is to provide automatic control of the idling and
maximum speeds to the engine and not of throttle or nozzle.
2158- Generally, the driver’s foot accelerator controls the intermediate speed of
the engine.
2159- The pneumatic governor functions due to the vacuum created by suction in
the air inlet pipe of the engine while in a mechanical governor, the camshaft
of the pump is fitted to two ball weights.
2160- Generally, when the mechanical governor is running on ‘no load’ position,
the ball weight do not fly.

13- Fuel Injector:

2161- Generally, quick and complete combustion is ensured by a well-designed fuel
injector.
2162- When the fuel is atomized into very fine droplets, it increases the surface
area of the fuel droplets.
2163- Generally, atomization is done by forcing the fuel through a small orifice
under high pressure.
2164- The injector assembly consists of
i) a needle valve
ii) a compression spring
ii) a nozzle
iv) an injector body.
2165- When the fuel is supplied by the injection pump, it exerts sufficient force
against the spring to lift the nozzle valve as only through nozzle the fuel is
sprayed.
2166- Generally, fuel is sprayed into the combustion chamber in finely atomized
particles.

14- Nozzle:
2167- Nozzle is that part of an injector through which the liquid fuel is sprayed into
the combustion chamber while governor is a part used inside engine.
2168- Atomization is the first phase in obtaining proper mixing of the fuel and air
in the combustion chamber whereas vaporization is the escaping of liquid.

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2169- Higher the injection pressure better the dispersion and penetration of the
fuel into all the desired locations in combustion chamber.
2170- When the density of compressed air in the combustion chamber is high then
the resistance to the movement of the droplets is higher and dispersion of
the fuel is better.
2171- When the fuel strikes the walls of combustion chamber, decomposes and
produces carbon deposits as it can only be decomposed in carbon and not in
iron and ashes.
2172- The circumferential hole nozzle is used in open type combustion chambers
and single or multi hole nozzle are not used.
2173- The size of the hole in a single hole nozzle is usually less than 0.2 mm for
better sprinkling of fuel.
2174- The spray cone angle is usually in the range of 50 to 150 in a single hole nozzle.
2175- The number of holes in a multi-hole nozzle, lies between 4 to 18 depending
on the size and requirement of the engine.
2176- The hole diameter in a multi-hole nozzle, lies between the range of 0.25 to
0.35 mm for the better fuel flow in the combustion chamber.
2177- The hole angle in a multi-hole nozzle, lies between 200 to 450 for better fuel
combustion.

15- Fuel Injection in S.I. Engine:

2178- The injection of fuel into a SI engine can be done by
i) direct injection of fuel into the cylinder
ii) injection of fuel close to the inlet valve
iii) injection of fuel into the inlet manifold.
2179- When manifold injection is contemplated, generally, continuous injection is
adopted.
2180- Generally, in timed injection, fuel is injected only during induction stroke
over a limited period.
2181- Generally, the fuel injection in an SI engine increases volumetric efficiency.
2182- Lower exhaust emission is obtained by using fuel injection in an SI engine.
2183- Of all the gasoline injection system, the most accurate gasoline injection
system is port injection.
2184- The main advantage of fuel injection in SI engine is increased volumetric
efficiency.

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UNIVERSITY RAWALPINDI)

16- Injection Timing:

2185- The injection of fuel into the inlet manifold of each cylinder is at different
timing.
2186- Injection timing is defined as the timing at which the injection of the fuel
takes place inside the inlet manifold.
2187- Only in one cylinder, the piston moves up from BDC to TDC during the
exhaust stroke and not in two or three cylinder engines.
2188- Just before the piston reaches TDC during exhaust stroke, injection of the
fuel takes place into the inlet manifold of the cylinder at about 60º crank
angle before TDC.
2189- An ignition process obeys the law of conservation of energy as energy is only
produced there.

17- Battery Ignition System:

2190- The battery used in vehicles are between 6 V to 12 V, so in battery ignition
system, the energy required for producing spark is obtained from a 6 V to 12
V battery.
2191- The essential components of a battery ignition system are
i) battery
ii) ignition switch
iii) ballast resistor
iv) ignition coil
v) contact breaker
vi) capacitor
vii) distributor
viii) spark plug.
2192- The battery is charged by a dynamo driven by the engine and shaft and axle
are not used in a battery.
2193- A lead acid battery consists of a number of cells connected together in series
and each having a nominal potential of 2 volts when fully charged.
2194- The lead acid battery is used in light duty commercial vehicles while alkaline
battery is used in heavy duty commercial vehicles.
2195- Battery is connected to the primary winding of the ignition coil through an
ignition switch and blast resistor.

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2196- When the ignition switch is closed, the primary winding of the coil is
connected to the positive terminal post of the storage battery.

18- Abnormal Combustion:

2197- Diesel knock occurs when the delay period is excessively long so that there
is a large amount of fuel in the cylinder for the simultaneous explosion phase.
2198- The rate of pressure rise per degree of crank angle is then so great that an
audible knocking sound occurs.
2199- Knock is a function of the fuel chosen and may be avoided by choosing a fuel
with characteristics that do not give too long a delay period.
2200- If detonation is allowed to persist under extreme conditions or over many
engine cycles, engine parts can be damaged or destroyed.
2201- Detonation is prevented by reducing peak cylinder pressure.
2202- Knock is less common in cold climates as compared to hot and moderate
climates.
2203- Diesel knock is the sound produced by the very rapid rate of pressure rise
during the early part of the uncontrolled second phase of combustion.
2204- In a spark ignition engine combustion which is initiated between the spark
plug electrodes spreads across the combustible mixture.
2205- A definite flame front is one that separates the fresh mixture from the
products of combustion travels from the spark plug to the other end of the
combustion chamber.
2206- In SI engine, due to the increment of the initial temperature and pressure are
ignition lag is reduced.
2207- Auto ignition refers to the initiation of combustion without the necessity of
a flame.
2208- The effects of knocking are
i) noise and roughness
ii) mechanical damage
iii) carbon deposits
iv) increase in heat transfer
v) decrease in power output and efficiency
vi) preignition.
2209- Low engine speeds will give low turbulence and low flame velocities and
knock may occur at low speed.

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19- Delay Period:

2210- Delay period is defined as the time immediately following injection of the
fuel during which the ignition process is being initiated and the pressure does
not rise beyond the value it would have due to compression of air.
2211- The delay period extends for about 13º, movement of the crank.
2212- The time for which delay period occurs decreases with increases in engine
speed.
2213- Delay period serves a useful purpose in that it allows the fuel jet to penetrate
well into the combustion space.
2214- The delay period depends upon temperature and pressure in the cylinder at
the time of injection.
2215- Delay period is directly proportional to load, so the delay period increases
with load.
2216- The delay period depends upon the nature of the fuel mixture strength.
2217- Higher cetane number means a higher delay period and smoother engine
operation.
2218- Compression ratio is indirectly proportional to delay period, so an increase
in compression ratio reduces delay period.
2219- At constant speed, delay period is proportional to the delay angle.
2220- A pre-combustion chamber gives a shorter delay compared to an open type
of combustion chamber.

20- Engine Cooling System:

2221- As a gasoline engine works on a mixture of air and gasoline, therefore the
gasoline engine requires much more air than a diesel engine.
2222- As the turbocharged engine produces less heat so, the turbocharged diesel
engine requires less cooling air than naturally aspired diesel engines.
2223- The heat flow to water jackets, on an average is about 4200 kJ/kW-h for large
engines and it is about 500-5700 kJ/kW-h for small engines.
2224- The outlet cooling water temperature for large engines is about 50ºC and the
outlet cooling water temperature for medium engines is 60 to 65ºC.
2225- The outlet cooling water temperature for small engines is 80ºC while the
outlet cooling water temperature for medium engines is 60 to 65ºC and the
outlet cooling water temperature for small engines is 80ºC.

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2226- In thermo-syphon system, the radiator should be kept well above the engine,
to provide a height for natural circulation.
2227- In liquid cooling, the cylinder walls and heads are provided with jackets
through which the cooling liquid can circulate.
2228- In liquid cooling, the liquid becomes heated in its passage through the jackets
and is itself cooled by means of an air-cooled radiator system.
2229- The coolant to be employed in liquid cooling system should have
i) low freezing temperature
ii) a high boiling point
iii) a large latent heat of vaporisation
iv) non-corrosive
v) easily and cheaply available.
2230- Commonly used anti-freeze materials are
i) denatured alcohol
ii) wood alcohol
iii) glycerin
iv) kerosene
v) sugar solution
vi) calcium or magnesium chloride
vii) ethylene glycol and proplene glycol.
2231- The various methods used for circulating water around the cylinder and
cylinder heads are
i) thermo-syphon cooling
ii) forced or pump cooling
iii) cooling with thermostatic regulator
iv) pressurized water cooling
v) evaporative cooling.
2232- In thermo-syphon cooling system, the cooling only depends on
temperature and is independent of the engine speed.
2233- The circulation of water starts only after the engine has become hot
enough to cause thermo-syphon.
2234- Components of the water cooling system are
i) water jacket
ii) water pump
iii) fan

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iv) thermostat
v) connecting hoses
vi) radiators
vii) radiator cap.
2235- Air cooling system is used in small engines whose application gives extreme
importance to weight such as aircraft engines while air cooling system is
used in industrial and agricultural engines where there can be a strong
objection to use of water as a coolant.
2236- Air cooling system is used in industrial and agricultural engines where there
can be a strong objection to use of water as coolant while air cooling
system is used in small engines whose application gives extreme
importance to weight such as aircraft engines.
2237- The design of the engines in air-cooled system becomes simpler, as no
water jackets are required.
2238- In air-cooled engine, high mean cylinder temperatures mean reduced
carbon deposits on the combustion chamber wall.

h) Environmental Engineering:
1- Water Demand:
2239- The average domestic water demand in Pakistan is 135 litres per capita per
day. For developed countries, average domestic water demand is around 340
lpcd because they live a luxurious life.
2240- The minimum water pressure available at fire hydrants is 100-150kN/m2 i.e
10-15m of water head and it should be maintained for 4 to 5 hours.
2241- Water loss in thefts and wastes contributes to 15% of total consumption,
which includes the water loss due to leakage or stolen due to illegal
connection.

2- Physical characteristic of Water:

2242- Size of suspended solids – 10-1 – 10-3 mm, size of colloidal solids – 10-3 – 10-
6
mm, size of dissolved solids < 10-6 mm.
2243- The maximum permissible limit for suspended solids is 30mg/l for testing
waste water which is set by the Environmental Protection Agency (EPA).

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UNIVERSITY RAWALPINDI)
2244- Dissolved solid is the difference between total solid and suspended solid.
Suspended solid is non-filterable solid whereas dissolved solid is filterable
solid.
2245- The colors in water are measured by Tintometer method. It is measured on
Burgess scale or cobalt scale by Nessler’s tube.
2246- 1 TCU (True Color Unit) is equivalent to color produced by 1 mg of platinum
cobalt in 1L of distilled water. The true color unit is also called a Hazen unit.
2247- The maximum value of Threshold odour number is 3 and its range is 1-3. The
threshold odour number is used to measure the intensity of taste and odour.
2248- TON testing is preferred in cold water as in hot water due to increase in
temperature, taste and odour can change.
2249- To do the temperature test of water, its temperature should be between
100C and 250C and the temperature higher than 250C is considered
objectionable.
2250- According to WHO, the permissible limit for drinking water is 5NTU.
2251- The value of turbidity measured by nephelometer is expressed in terms of
NTU. Sometimes, it is referred as FTU or Formazin turbidity unit.
2252- Turbidity rod is inserted inside the water and the reading at which needle
becomes invisible gives the turbidity.

3- Types of Screens and Aerators:

2253- Screens are used as a pretreatment process for purification of water to avoid
large size suspended materials from water.
2254- Coarse screens are used in the form of bars of 25mm diameter size and are
spaced at 75 to 100mm centers.
2255- The coarse screen is inclined at 450-600 so that they can be easily cleaned
with a rake. Moreover, it reduces the flow velocity which also helps in
cleaning the screen.
2256- Aeration reduces the carbon dioxide content and corrosiveness of water and
hence, raises the pH value of water.
2257- Cascade aerators are the gravity aerators in which water falls from 1-3m
height such that it comes in contact with air and reduces carbon dioxide
content to 50-60%.

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2258- In Cascade aerator, the flow of water is divided into fine streams and small
droplets such that they come in contact with air in their trajectories and
reduces CO2 by 70-90%.
2259- Automatic strainers are self cleaning devices that remove solids from the
flowing liquid continuously and help in a fine screen so that it does not get
clogged up.

4- Theory and classification of Filtration:

2260- Filtration is a primary turbidity removal process. It also removes color,
suspended solids and fine particles.
2261- In Mechanical Straining, particles coarser than the void size is arrested. The
water passing the voids will be free from such particles.
2262- In the sedimentation action of filtration, colloidal particles arrested in the
voids attract other finer particle, settle down in the voids and get removed.
2263- Schmutzdecke zone is the first zone of purification in a sand bed. It comes
under the biological action of filtration. Schmutzdecke is known as the
surface coating.
2264- Schmutzdecke is a film of algae, bacteria and protozoa formed on the
uppermost layer of sand which helps in the breakdown of organic impurities
into harmless compounds acting as a fine mesh straining mat.
2265- Filter removes the particulate matter by electrostatic exchange where the
charge of the filter medium neutralizes the charge of the floc and permitting
it to be removed.
2266- In Slow sand filter, rate of filtration is low and due to this they requires large
land and are expensive to install.
2267- The surface coating is formed by the reddish brown deposit of partially
decomposed organic matter together with Iron, Alumina, Manganese and
Silica.
2268- In Heterotrophic zone, bacteria multiplies in large number, breaks down not
only the organic matter but also destroys each other to maintain a balance
of life in the filter.
2269- The surface area of the slow sand filter lies between 50m2 to 1000m2 and its
filtration rate lies between 100 to 200 litres of water per m2.

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2270- Rapid sand filter is cheap and economical and its period of cleaning is 1-2
days. Neither the coagulation nor the skilled supervision is required in the
slow sand filter.

5- Slow Sand Filter:

2271- The depth of an enclosed tank of a slow sand filter lies in the range of 2.5-
4m and its surface area lies between 50-1000m2.
2272- When the fineness of sand increases, the bacterial efficiency increases, but
rate of filtration decreases. Fine sand is preferred when high bacteria and
turbidity removal efficiency is desired.
2273- The base material consists of 30-75 cm thick gravel bed which is laid in layers
of 15 cm with finer topmost layer and coarser bottom layer.
2274- The minimum number of filter beds provided in the slow sand filter is 2
where one unit is provided as stand by for an area of 20m2.
2275- The slow sand filter is not efficient in removing turbidity of water and is not
capable of removing turbidity over 50ppm.
2276- The slow sand filter is designed for maximum daily demand, which is 1.8
times the average daily demand.

6- Rapid Sand Filter:

2277- The depth of an enclosed tank of a rapid sand filter lies in the range of 2.5-
3.5m and its surface area lies between 20-50m2.
2278- The effective size of a rapid sand filter lies in the range of 0.35-0.6mm and
its common value is 0.45mm.
2279- The finer the suspended impurities to be removed, smaller will be the sand
size in order to increase the surface area of sand grains in the sand bed.
2280- The value of uniformity coefficient in a rapid sand filter lies between 1.2 and
1.7 and its common value is 1.5.
2281- The effective size of Anthracite when used as a filter material lies between
0.7-0.75mm and its uniformity coefficient is 1.75.
2282- Anthracite is a costlier filter material used in industrial filter which is more
inert to hot caustic solutions than sand.
2283- The base material of a rapid sand filter consists of 45-60 cm thick gravel bed
which is laid in layers of 15 cm with a finer topmost layer (2-6mm) and
coarser bottom layer (20-50mm).

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2284- Air compressor is used to supply air for the agitation of sand grains at the
rate of 0.6-0.8m3 per minute per m2 of filter area for 5 minutes.

7- Methods of Disinfection:
2285- Disinfection is a process which is done to kill microorganism present in the
water after the filtration process.
2286- Disinfection should not render the water toxic, objectionable and
unpalatable for its intended use.
2287- Boiling of water is a physical method of disinfection which is also called as
disinfection by heat.
2288- Sunlight is a natural disinfection. Irradiation by ultraviolet rays promotes
disinfection.
2289- The pathogenic get killed at pH>11 which is very alkaline in nature or at pH=3
which is highly acidic.
2290- Boiling method is effective in complete sterilization of water as it kills all the
bacteria and microorganism present in water.
2291- The dose of lime used in the excess lime treatment is 10-20ppm and the
excess lime can be removed by the process of re-carbonation.
2292- The depth of water while using ultra violet ray treatment for disinfection
should not exceed 10 cm and its turbidity should be in the range of 15-
20ppm.
2293- The Potassium permanganate treatment is used in rural areas where most of
the water is drawn from a well which contains the least amount of bacteria.

8- Chlorination:
2294- The chlorine existing in water as hypochlorous acid, hypochlorite ions,
molecular chlorine is termed as free available chlorine.
2295- When chlorine is added to water, the chlorine acts as molecular chlorine only
when its pH is less than 5.
2296- When the pH is between 5 and 10, the chlorine in the water acts as
hypochlorous acid and hypochlorite ions. As pH increases, the concentration
of hypochlorous acid decreases while of hypochlorite ions increases.
2297- The hypochlorous acid is 80 times more effective as hypochorite ions, so the
pH of water to be treated should be less than 7 to prevent the ionization of
it.

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2298- Chlorine has the oxidizing power which oxidizes organic and inorganic
impurities present in water and the amount of chlorine, which gets
consumed before disinfection is called as chlorine demand.
2299- When chlorine demand is fulfilled, then chlorine is available s free residual
chlorine, which contains hypochlorous acid and hypochlorite ions.
2300- The water is satisfactorily disinfected if the free residual chlorine is 0.2 ppm
at the contact period of 10 minutes.
2301- The chemical formula of bleaching powder is Ca (OCl)2. It is called as
chlorinated lime.
2302- The process of chlorination with hypochlorites is called Hypo-chlorination.
Hypochlorites are applied to water as a solution by the hypochlorite feeding
apparatus.
2303- The disinfecting reaction with chloramine are slower than with chlorine
alone, so the contact period of 2 hours is provided.

9- Types of Pumps:
2304- The pumps are classified on the basis of the mechanical operation of the
principle, type of power and type of service.
2305- Mechanical principle of operation is classified into displacement, centrifugal,
air lift and miscellaneous pumps.
2306- Pumps are of four types on the basis of type of service- low lift, high lift, deep
well and booster pump.
2307- There are 3 types of pumps on the basis of type of power. They are – steam
engine, diesel engine and electrically driven pump.
2308- Booster pump is classified on the basis of type of service. They are used for
increasing gas pressure, transferring high pressure gas, scavenging and
charging gas cylinders.
2309- The centrifugal pump has a continuous flow. It does not give a constant
discharge under variable head.
2310- The speed at which the centrifugal pump runs lies in the range of 500 to 100
rates per minute (r.p.m). The direct connection of pump with driving
machines is possible.
2311- The efficiency of the centrifugal pump lies between 40% and 85%. It depends
on the head and discharge of the pump.

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2312- Based on the type of casing, the centrifugal pump is divided into the volute
pump and turbine pump.

10- Centrifugal Pump:

2313- The impeller in the volute pump is surrounded by a spiral shaped casing
called as volute chamber. The shape of the casing is such that the sectional
area of flow around impeller increases from the tongue to delivery tube.
2314- The advance version of volute chamber is designed by J. Thomson where a
circular chamber called vortex chamber is provided between the impeller
and the volute chamber.
2315- A diffuser pump is a reverse pump, so it is also called a turbine pump. It
contains a series of guide vanes surrounding the impeller.
2316- The centrifugal pump is divided into a single stage and multistage pump
depending on the number of impellers.
2317- The each stage in centrifugal pump increase the head from 30 to 45m. There
can be six stages in a centrifugal pump.
2318- Depending on the basis of the direction of flow, the centrifugal pump is
divided into the radial flow pump, mixed flow pump and axial flow pump.
2319- Based on the number of entrances to the impeller, the centrifugal pump is
divided into single suction and double suction pump. In a single suction
pump, the liquid enters from one side of the impeller.
2320- The specific speed of a centrifugal pump is given by NQ1/2 / H3/4 Where, N is
the rotational speed in rates per minute, Q is the discharge in litres/Sec and
H is the head in metres.
2321- The specific speed of the pump is given by NS = NQ 1/2 / H3/4 and when NS >
2600, the type of pump is centrifugal pump.

11- Reciprocating Pump:

2322- The reciprocating pump has a continuous flow. It has a constant discharge
even if head on the delivery side varies.
2323- The reciprocating pump runs at a low speed. Its speed is less than 30m/min.
If they are connected to driving machines, speed reducing devices are
necessary.
2324- The efficiency of the reciprocating pump lies between 40% and 85%. Long
stroke engines have 85% efficiency while smaller pumps have 40%.

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2325- At the double acting reciprocating pump, the liquid is in contact with both
sides of the plunger. It has two suction and deliver pipes having appropriate
valves.
2326- The reciprocating pump is divided into 5 types on the basis of number of
cylinders. It includes single cylinder, double cylinder, triple cylinder, duplex
double action and quintuplex pump.
2327- In a Triple cylinder reciprocating pump, each cylinder has its own suction and
delivery pipes and has a 1200 crank.
2328- Quintuplex pump has five single acting cylinders with separate suction and
delivery having 72ocrank.
2329- No valves are required in rotary pump and the flow is continuous. Gear, Lobe
and Vane pumps are the examples of rotary pump.
2330- The reciprocating pump has high initial and maintenance cost, more power
required and required large space.

12- Well Pump:

2331- The types of pumps that are used for lifting water from wells are Hand
pumps, Reciprocating pumps, Centrifugal pumps, Air lift pumps and Jet
pumps.
2332- Hand pumps are used specifically for shallow wells, whereas Reciprocating
pumps are used for deep wells.
2333- There are two types of hand pumps- Pitcher pump and Force pump. A Pitcher
pump consists of a cylinder in which a plunger moves up and down.
2334- The maximum number of impellers in a centrifugal well pump is 20 and it
depends on the head, mixed flow, propeller type with vanes and guide
passages.
2335- The diameter of turbine used in centrifugal well pump lies between 10 to
35cm and its length varies from 20 to 60cm.
2336- Strainer is provided at the entrance of suction pipe during centrifugal pump
installation to prevent the clogging otherwise it will damage the pump.
2337- When the pump is stopped, the foot valve prevents the water from leaving
the pump. Therefore, it acts as a self-priming device.
2338- Check valve is present at the entrance of the delivery pipe which prevents
the back flow of water through the pump.

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2339- The speed at which the pump will discharge a unit flow under a unit head at
maximum efficiency is called specific speed. It is denoted by NS.
2340- Specific speed is a dimensionless quantity which is given by NS = NQ1/2 / H3/4.
2341- When the specific speed lies between 5000 to 10,000, the type of the pump
is an axial flow pump.

13- Selection of Pumping Units:

2342- The plot of total dynamic head and discharge of a pump is called system head
curve and each point on it denotes the head which consists of total static
head, head loss in suction and delivery pipe.
2343- The operating point is the point of intersection of system head curve with
the head – discharge characteristic curve of the pump. It is also called as
operating range.
2344- The friction head is the sum of head Loss in the entire length of piping, head
Loss in bend tees and head Loss in valves.
2345- When the pumps are in parallel operation, then the total discharge is equal
to the sum of the discharges by each pump i.e Q = Q1 + Q2.
2346- When the pumps are in series operation, then at a given discharge, total
head is equal to the sum of heads added by each pump i.e H = H1 + H2.
2347- The efficiency of a pump depends on the amount of load. At half load, the
efficiency of the pump is 70%.
2348- The efficiency of the pump at quarter load is 50% and at full load, the
efficiency of the pump is 80%.
2349- The installed capacity of the pump depends on three factors, namely-
balancing storage, the maximum rate of hourly demand and the operation
schedule. The installed capacity of the pump is kept larger than the
maximum rate of demand.
2350- If the diameter of pumping mains decreases, then the velocity of flow will
increase for a given fixed discharge resulting in the increase of friction head
loss and velocity head and ultimately increases the total dynamic head.

14- Physical Characteristics of Waste Water:

2351- Turbidity represents the physical characteristic of water, whereas BOD, COD
and chloride content represents the chemical characteristic of water.
2352- The turbidity of waste water is measured in mg/L. The other units of turbidity
are ppm, NTU and JTU.

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2353- When the sewage becomes stronger, the milkiness in water increases and
thus, the turbidity increases.
2354- If the color of sewage is grey, yellow and light brown, then it means that the
sewage is fresh.
2355- The color of septic sewage is black or dark brown. It contains either little or
no oxygen.
2356- The odor in waste water is measured by Osmoscope which consist of two
10mm diameter glass tubes which is 300mm long and 8mm wide.
2357- The average temperature of sewage is 20oC. The temperature of sewage is
higher than that of the water supply.
2358- If the odor intensity of water is 6, it indicates extremely strong odor and
when it is 0, it indicates the odorless water.
2359- The color indicates the freshness of sewage. It can be detected easily by the
naked eye.
2360- The threshold odor number is equal to the volume of samples of water
required to add to 100 units of odorless fresh water at which the mixture
gives the first detectable odor.
2361- The odor quality of Amines is fishy and its chemical formula is CH3NH2.
2362- Ammonia has an ammoniacal type of odor quality and its chemical formula
is NH3.
2363- The wastewater from the kitchen is an example of grey water. It also includes
water from the bathroom without urine and feces.
2364- The type of wastewater from the flushing operation of toilet is black in color
and if it does not include urine, then it is brown in color.

15- Chemical Characteristics of Waste Water:

2365- The temperature and dissolved oxygen are inversely proportional to each
other.
2366- At least, 4ppm of dissolved oxygen should be present in treating sewage
otherwise, fishes will die due to lack of dissolved oxygen.
2367- The presence of Albuminoid nitrogen in water indicates the decomposition
of sewage has not taken place.It nitrogen is also called as organic nitrogen.
2368- The presence of free ammonia in sewage represents recent pollution. Which
can be removed from wastewater by the nitrification process.

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2369- Potassium chromate is used for the titration of waste water with silver
nitrate solution for finding the chloride content.
2370- The suspended solids float in sewage. 1000kg of sewage contain 0.112 kg of
suspended solids.
2371- The presence of nitrates indicates the old pollution. It also means that the
nitrogen is fully oxidized in sewage.
2372- Wrinkler method is used to find the D.O content of sewage where the D.O
content is proportional to the titration of iodine with S2O32- solution.
2373- Domestic sewage includes waste from kitchen, laundry, toilet, bathroom,
etc., which contain higher amount of chloride content, so the permissible
dose of 120ppm is kept for domestic sewage.
2374- The decomposition of sewage leads to the formation of sulfur compound like
H2S which produces a pungent smell.
2375- Methemoglobinemia is a disease caused due to lack of nitrates in the body
where the concentration of methemoglobin in red blood cells becomes
greater than 1%.
2376- At a given temperature, the maximum quantity of dissolved oxygen in
sewage in wastewater is called saturated dissolved oxygen.
2377- Chlorides are inorganic matter, whereas Fatty acids, Cellulose and Fats are
organic matter.
2378- The fresh sewage is alkaline, but after sometime, the production of acid takes
place and the pH of sewage decreases.

16- Biological Characteristics of Waste Water:

2379- Carbon dioxide is formed due to the oxidation and reduction of organic
matter by aerobic and anaerobic bacteria respectively.
2380- Carbonaceous organic matter (oxidation by aerobic bacteria) —–> CO2 +
H2O + Energy.
2381- The BOD of wastewater where oxidation of organic matter takes place is
very less in comparison to that formed by anaerobic oxidation, where BOD
of 5000ppm can be formed.
2382- Organic acids (oxidation by anaerobic bacteria) —–> CH4 + CO2 + Energy.
2383- Carbonaceous organic matter (reduction by anaerobic bacteria) —–> CO2 +
Energy.

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2384- Sulfurous organic matter (reduction by anaerobic bacteria) —–> H2S +
Energy.
2385- Partially oxidized sewage contains nitrites and sulfur whereas fully oxidized
sewage contains nitrates and sulfates.
2386- Sulfurous organic matter (oxidation by aerobic bacteria) —–> SO–4 + Energy.
2387- Nitrogenous organic matter (reduction by anaerobic bacteria) —–> N2 +
NH3 + organic acids + Energy.
2388- H2S is formed from the anaerobic oxidation of sulfurous organic matter.
2389- Aerobic oxidation gets completed only in single step, whereas anaerobic
oxidation gets completed in two steps.
2390- NO3 is formed due to the aerobic decomposition of nitrogenous organic
matter.
2391- Small amount of energy is released during the anaerobic oxidation in
comparison to aerobic oxidation of organic matter with a magnitude of 26
kilo calories.

17- Oxygen Demand:

2392- BOD is the amount of oxygen required to oxidize only organic matter in
sewage. It is always less than COD as COD oxidizes both organic and inorganic
matter.
2393- The full form of BOD is biochemical oxygen demand. It is measured in ppm
or mg/L.
2394- BOD = Dissolved oxygen * Dilution factor.
Where Dilution factor = Volume of diluted sewage sample / Volume of
undiluted sewage sample.
2395- The value of deoxygenation constant is directly proportional to the
temperature. It increases with increase in temperature.

18- Dispersion of Air Pollutants, Contol of Gaseous Pollutants:

2396- When the temperature increases with an increase in altitude, Sub adiabatic
lapse rate occur and there will be stable environment.
2397- Under negative lapse rate, the colder air is below the warmer air. It can be
occurred near the earth’s surface.
2398- When the temperature is constant with height, then neutral lapse rate
occurs.

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2399- The value of wet adiabatic rate is 60C per 1000m whereas of dry adiabatic
rate is 9.80C per 1000m.
2400- In Super adiabatic lapse rate, the environment is unstable due to the quick
dispersion of pollutants.
2401- Cyclone collector, Gravitation settling chamber and Dynamic precipitator are
used to remove particulate matter, whereas Plate tower is used to remove
gaseous matter and is an absorption unit.
2402- Activated alumina is used as a catalyst for removing gaseous pollutant called
hydrocarbons from the air. The concentration of hydrocarbon emitted from
automobiles is 300-1000 mg/l.
2403- Packed tower is a part of the absorption unit, whereas multiple fixed bed,
fluidized bed and moving bed are the examples of absorbers.
2404- Water is an absorbent whereas molecular sieves, activated carbon and
activated alumina are adsorbents.

19- Air Pollution – Analysis:

2405- Like the name suggests, opacity monitors or transmissometers work by
transmitting light into a particular stream of gas, and gives information
regarding the combustion conditions and efficiency.
2406- These monitors are used to measure the concentrations of certain gases such
as oxygen, carbon monoxide, oxides of sulphur and nitrogen from the
exhaust.
2407- Fluorescence occurs when a molecule is excited by light energy of specific
wavelength and emits light energy of another wavelength.
2408- Electroanalytical instruments rely on polarography, conductivity,
electrocatalysis and amperometric analysis.
2409- Electrocatalytic analysers are used for oxygen monitoring.
2410- In-site in-stack analysers work on the principle of second derivative
spectroscopy to measure concentrations of ammonia, sulphur dioxide and
nitrogen monoxide.
2411- Conductometric analysis is a non-specific method and hence requires
interfering gases to be removed before monitoring process.
2412- The primary standard level for carbon monoxide is 9ppm.
2413- Respiratory bronchiole, alveoli and alveoli ducts are categorised under the
pulmonary section of the respiratory tract.

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2414- The thin walls of the alveoli contain capillaries which aid in transfer of oxygen
and toxic substances into the blood and removal of carbon dioxide.
2415- The velocity of air reduces to zero only when it reaches the alveoli and not
the bronchi.
2416- The moist nasal passage can capture dust particles above 10 micrometre.
2417- Ozone scars lung tissues when exposed for a long time and it intensifies
asthma by increasing the individual’s sensitivity towards allergens.
2418- Ozone is the major constituent of photo-chemical smog.
2419- Sulphur dioxide interrupts our immunity towards particulate matter and
allows bacteria to enter through our respiratory system.
2420- Generally, air pollution increases with increase in temperature because it
leads to increase in ground level ozone, nitrogen dioxide concentrations
increase since higher temperature favours the oxidation of nitrogen
monoxide.
2421- It was earlier assumed oceans served as a sink, but marine organisms
contribute enough carbon monoxide to highly saturate the ocean surface.
2422- Carbon monoxide has higher affinity to bind with haemoglobin and does not
allow binding of oxygen.
2423- Nitrogen dioxide destroys macrophages and injures lung’s defence
mechanism thereby making us more vulnerable to air-borne pathogens.
2424- Metal processing, namely lead smelting is the major cause for presence of
lead in air.
2425- Lead has extreme effects on the human body like increase in blood pressure
and damages the organs and reproductive system.
2426- Crocidolite, actionide and amosite are amphiboles which is a type of
asbestos.
2427- Tomato is sensitive towards sulphur dioxide whereas onion, potato and corn
are relatively tolerant.
2428- Ozone is not a primary pollutant since it is formed by the photo-chemical
reaction of oxygen with the UV rays and not directly discharged into the
atmosphere by a source.
2429- Nearly 90% of the air pollutants are gases.
2430- Organic pollutants are those which primarily contain hydrogen and carbon.
Carbon Monoxide is inorganic since it does not contain hydrogen.

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2431- Criteria pollutants are those pollutants which are classified and standardized
because of their high potency to cause harm.
2432- Sewage treatment plants pose as a major contributor to air pollution
because of the discharge of gases such as methane, oxides of sulphur and
nitrogen.
2433- Methane is highly abundant since it is released during decaying process of
dead matter.
2434- VOC is used as an abbreviation for Volatile Organic Compounds.
2435- Generally, VOCs have low vapour pressure enabling them to exist in
atmosphere as gases.
2436- Ethylene. It is not toxic to human beings or animals, but has adverse effects
on plants when present at very small concentrations as well and hence acts
as an air pollutant.
2437- Polynuclear Aromatic Hydrocarbons such as Benzo-(a)-pyrene, is a type of
pollutant that is released from a burning cigarette.
2438- The residence time is the average time a particle remains active in a given
system.
2439- It has 200 times greater affinity for haemoglobin than oxygen.
2440- Sulphur dioxide has a pungent odour which can be detected in even in very
minute concentrations in the range of 0.1 – 0.3 parts per million.
2441- Denitrifiers (such as ammonia oxidising bacteria) in aerobic conditions serve
as the major producer for nitrous oxide.
2442- The method of spraying pesticides leads to small portion of pesticide serving
as an air pollutant. Some pesticides evaporate from soil and pollute the air.
Eg. DDT.
2443- Pollen grains are the most significant air-borne allergen with an
indestructible outer membrane, and are known to cause severe respiratory
problems when inhaled.
2444- Borane is mixed with petroleum and used as a fuel in rockets and jets which
when combusted releases boron which causes air pollution.
2445- Arsenic is a human carcinogen and is emitted during the combustion of coal
and petroleum. It is also found in detergents, pesticides and mine tailings.

20- Meteorology:
2446- Meteorological information is necessary predict and plan the control of air pollution.

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2447- Tetroon – Tetrahedral Balloon drifts horizontally along with the wind and is tracked
by radar. It is used to analyse local wind patterns.
2448- Richardson number (-Ri) gives a relative rate of production of mechanical and
convective energy.
2449- Beyond Richardson number of 0.25, the vertical mixing comes to a standstill and
weak horizontal eddies alone remain.
2450- When Richardson number is zero, there is mechanical turbulence alone.
2451- Between 0 and -0.03, both mechanical turbulence and convective mixing are
present, but mechanical turbulence is greater. Below -0.04, convective mixing
starts dominating.
2452- Anticyclones are high pressure regions with low ventilation where air is sinking,
and is warmed by compression.
2453- Turbidity is the term used to describe reduction in light/visibility due to smoke and
other dust particles. Due to air pollution, about 15-20% reduction in sunshine is
observed in cities.
2454- Water vapour varies based on time and place at the atmospheric boundary level
due to the continuous action of evaporation and condensation near water bodies.
2455- At first the pressure gradually decreases with increase in altitude, and with further
increase the rate at which pressure drops starts increasing.
2456- Obliquity is the term used to indicate the Earth’s axial tilt which is responsible for
the seasonal variations across the northern and southern hemispheres.
2457- Geostrophic winds are those winds which blow parallel to isobars when the both
the Coriolis force and pressure gradient force are balanced.
2458- Albedo indicates the fraction of solar energy that is reflected back to space. Fresh
snow/ice has the highest albedo due to its reflective properties.
2459- The ozone layer in the stratosphere absorbs radiations (mainly UV) coming from
the sun. This energy is the key to stratospheric stability.
2460- Climate is affected by latitude, elevation, ocean currents, etc.

21- Atmosphere:
2461- Nitrogen constitutes 78% of the atmosphere. So 78% of one million =
780,840 ppm – is the concentration of nitrogen gas in the atmosphere.
2462- In the lower layers of atmosphere, light of wavelengths greater than 300nm
are present and it is because of this reason, there is generally no ozone
formation at the ground level.
2463- Specific humidity is the mass of water vapour per unit mass of air mixture.
2464- Doldrums are the irregular winds and their exact location is hard to analyse.
Ships in the region of doldrums might restrict its movement due to a lack of
proper wind.

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2465- Roaring forties found in the southern hemisphere are strong westerly winds
caused by air displaced from the equator to the South Pole and aid
yachtsmen in on competitions and voyages.
2466- Troposphere is nearly 16-17km thick at the equator and thins down to
approximately 8km at the poles.
2467- Temperature slightly increases with altitude in the stratosphere due to
absorption of UV radiations from the sun, by the ozone layer present in the
stratosphere.
2468- Exosphere is the outermost layer of the atmosphere followed by
mesosphere, thermosphere, stratosphere and troposphere.
2469- Ionosphere is a secondary layer of the atmosphere which extends through
mesosphere, thermosphere and exosphere during day time and is
responsible for aurora – natural light display in the sky in high altitude
region.
2470- Homospheric layers of atmosphere include layers where chemical
composition is independent of molecular weight of gases due to mixing by
turbulence. Hence the lower layers such as troposphere, ionosphere and
mesosphere are homospheres.
2471- Turbopause marks the height at which homogenous layer, the homosphere
ends. Below the turbopause, turbulent mixing of air dominates.
2472- The planetary boundary layer is the lowermost level of the atmosphere and
it belongs to the troposphere.
2473- As per International Standard Atmosphere, at sea level atmospheric
pressure is equal to 101325 Pa which is equal to 14.696 psi and 760 Torr.

22- Climate Model:

2474- Without greenhouse gases, the Earth’s average temperature (currently
about 14oC), would have been 33oC less.
2475- Since the industrial revolution, the average temperature of earth has
increased by 0.6oC due to consumption of fossil fuels.
2476- The greenhouses gases, mainly carbon dioxide and water vapour absorb
nearly 75 peta-watts of the infrared radiations from the sun.
2477- Earth has an emissivity of 0.457.

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2478- As per definition, ice age refers to the period when there are large ice
sheets in both the hemispheres. Antarctica, Greenland and Arctic ice sheets
are the reason we are still in Holocene of the ice age.
2479- Ionosphere contains ionized atmospheric particles due to solar radiation
and is useful in the propagation of radio waves.
2480- Tropospheric layer extends up to 17km in altitude at the equator and is
known to contain 80% of the mass of the atmosphere.
2481- Overcast is a phenomenon where cloud cover is equal to 8 oktas (unit of
measurement) and shadow cannot be seen due to indirect radiation caused
by scattering.

23- Greenhouse Gases:

2482- Due to excessive combustion of fossil fuels, the carbon dioxide
concentration shot up from 280ppm during 1750 to nearly 400ppm
recently.
2483- Water vapour also helps in trapping sun’s heat energy and thereby serves
as the most abundant greenhouse gas.
2484- The word “anthropogenic” stands for environmental impact due to human
activity.
2485- Carbon dioxide dissolves in water as not only gas but also in the
bicarbonates form. Therefore, ocean is one of the major sinks for carbon
dioxide.
2486- Titan, Mars and Venus contain several greenhouse gases in their
atmosphere and exhibit greenhouse effect.
2487- Titan also exhibits anti-greenhouse effect. The haze, constituting organic
molecules, is not very efficient in trapping infrared radiations and thereby
reduces the temperature by 9 K.
2488- Greenhouse gases trap the infrared radiations from the sun and reflect it
back to the Earth’s surface thereby heating up the planet.
2489- The airborne fraction (AF) indicates the proportion of GHG emissions that
remain after a given time.
2490- Clouds can absorb infrared radiation as well as emit them and hence
contribute to greenhouse effect.

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2491- Global warming potential indicates the heat trapped by a greenhouse gas
over 20, 50 or 100 years in terms of equivalent heat trapped by carbon
dioxide over the same period of time.
2492- The global warming potential of a given gas depends on its absorption
capability over range of IR wavelengths and how long it stays in the
atmosphere.
2493- Perfluorotributylamine used as in heat transfer and electrical industry has
the highest radiative efficiency, i.e. it can effectively trap the long wave
radiation better than other greenhouse gases.
2494- Sulphur hexafluoride has a potential of warming the planet 16,300 times
greater than carbon dioxide.
2495- Natural sources of CO2 are twenty times greater than anthropogenic
sources, but at the same time they are balanced out by various other
natural processes.
2496- Lack of moisture, i.e. water vapour, prevents re-radiation of the IR rays
from the surface, thereby not trapping heat. Hence desert has high
temperatures during the day and extremely low temperatures in the night.
2497- Enhanced weathering is a form of geo-engineering where minerals are
broken down to help remove CO2 from air.
2498- Carbon sequestration is the process of removal of CO2 and storing them in
carbon sinks to minimise their impact on global warming.
2499- Wetlands, old oil fields, saline waterbodies, etc. are important carbon
storages and help in removal of CO2 from atmosphere.
2500- Methane is a gas released by the digestive processes of cattle and hence
cattle farming also contribute to greenhouse effect.
2501- Volcanic eruptions release sulphate aerosols which help in blocking sun’s
radiations from reaching the Earth’s surface. Hence they aid in generating a
cooling effect.

24- Ozone Depletion:

2502- The concentration of ozone is about 10 ppm in the ozone layer and only 0.3
ppm in the entire atmosphere.
2503- In 1913, Henri Buisson and Charles Fabry discovered the ozone layer and
later its properties were studied by G.M.B. Dobson.

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2504- The spectrophotometer developed by Dobson can be used to measure ozone
in the stratosphere from the ground. The amount of ozone is measured in
terms of – Dobson unit.
2505- The ozone layer absorbs the medium frequency UV radiations from the sun
and hence protects the life forms at the surface from harm.
2506- Sydney Chapman was the physicist who discovered that stratospheric ozone
if formed when the UV rays from the sun splits oxygen molecules, and the
nascent oxygen combines with existing molecules to form ozone.
2507- The ozone layer is found in high concentrations of 2-8ppm at an altitude of
20-40km.
2508- Nitrogen prevents extremely short wavelengths or vacuum UV radiations
(10-100nm) from reaching the surface.
2509- UV-B radiations of 315-280nm is responsible for causing sunburns, genetic
damage as well as skin cancer.
2510- The longest of the UV-B radiations reach the surface of the earth is small
fractions and aids in vitamin D production of the skin.
2511- The ozone levels in the northern hemisphere are at maximum during the
spring season.
2512- The ozone hole was discovered in the year 1984 by Jonathan Franklin, Joseph
Farman and Brian Gardiner.
2513- The phenomenon of the ozone hole occurred in the Antarctic region
primarily due to catalytic breakdown of ozone molecules by halogenated
compounds.
2514- Refrigerants containing halocarbons, foam-blowing agents such as HFCs,
halons, CFCs and freons as well as propellants containing halogenated
compounds are responsible for depleting the ozone layer.
2515- The Montreal protocol bans the production of halons, trichloroethane, CFCs
and carbon tetrachloride.

25- Acid Rain:

2516- Though the pH of neutral water is 7, rain water is acidic due to mixing up with
atmospheric carbon dioxide and is said to have a 5.6 pH. Hence acid rain has
a pH less than 5.6.
2517- Glass containers can alter the pH of the rain water and hence not suitable to
use for sampling rain water.

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2518- Sulphur dioxide and nitrogen dioxide have a high tendency to mix with water
to form sulphurous/sulphuric acid and nitric acid.
2519- Liming is done to neutralise soils that become acidic due to excessive acidic
rainfall, but is known to have harmful impact on plant life.
2520- The phenomenon of acid rain was discovered by Robert A. Smith during the
industrial revolution.
2521- Though primary natural contributor to sulphur dioxide is volcanic eruptions,
even sea sprays and decaying vegetation release sulphur dioxide to the
atmosphere.
2522- Aquatic organisms require a moderately acidic pH of 4.8 and if it goes below
this level, it proves to be detrimental to their survival.
2523- The acidic air pollutions get deposited on the Earth’s surface due to both wet
and dry deposition. Wet deposition occurs due to rain fall and moist weather,
whereas dry deposition occurs due to mixing of acidic pollutants and dust.

General Topics of FMP:

2524- Tillage:
Tillage is the agricultural preparation of soil by mechanical agitation of
various types, such as digging, stirring, and overturning. Examples
of human-powered tilling methods using hand
tools include shoveling, picking, mattock work, hoeing, and raking. Examples
of draft-animal-powered or mechanized work
include ploughing (overturning with moldboards or chiseling with chisel
shanks), rototilling, rolling with cultipackers or other rollers, harrowing, and
cultivating with cultivator shanks (teeth).
Tillage that is deeper and more thorough is classified as primary, and tillage
that is shallower and sometimes more selective of location is secondary.
Primary tillage such as ploughing tends to produce a rough surface finish,
whereas secondary tillage tends to produce a smoother surface finish, such
as that required to make a good seedbed for many crops. Harrowing and
rototilling often combine primary and secondary tillage into one operation.
"Tillage" can also mean the land that is tilled. The word "cultivation" has
several senses that overlap substantially with those of "tillage". In a general
context, both can refer to agriculture. Within agriculture, both can refer to
any kind of soil agitation. Additionally, "cultivation" or "cultivating" may

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MCQS BANK FOR POSTS OF ASSISTANT AGRICULTURAL ENGINEER/WATER MANAGEMENT OFFICER/
LANDSCAPE ENGINEER/ ASSISTANT DIRECTOR 2021 Edition (PPSC, FPSC, NTS, OTS, PTS CTS).
(COMPILED THROUGH VARIOUS SOURCES BY ENGR.ANEES.KAMRAN/PMAS ARID AGRICULTURE of
UNIVERSITY RAWALPINDI)
refer to an even narrower sense of shallow, selective secondary tillage
of row crop fields that kills weeds while sparing the crop plants.
Primary and secondary tillage:
Primary tillage is usually conducted after the last harvest, when the soil is
wet enough to allow plowing but also allows good traction. Some soil
types can be plowed dry. The objective of primary tillage is to attain a
reasonable depth of soft soil, incorporate crop residues, kill weeds, and to
aerate the soil. Secondary tillage is any subsequent tillage, in order to
incorporate fertilizers, reduce the soil to a finer tilth, level the surface, or
control weeds.

293
MCQS BANK FOR POSTS OF ASSISTANT AGRICULTURAL ENGINEER/WATER MANAGEMENT OFFICER/
LANDSCAPE ENGINEER/ ASSISTANT DIRECTOR 2021 Edition (PPSC, FPSC, NTS, OTS, PTS CTS).
(COMPILED THROUGH VARIOUS SOURCES BY ENGR.ANEES.KAMRAN/PMAS ARID AGRICULTURE of
UNIVERSITY RAWALPINDI)

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