Assignment 1

Due date: 2019-08-14, 23:59 IST.

Assignment not submitted
1 point
A simple compressible closed system, initially at a specified state point, receives a specific
quantity of heat while undergoing a reversible process. Among the following possible processes,
which one will correspond to the largest change in the specific internal energy?

reversible isobaric process

reversible isochoric process
reversible isothermal process
reversible isentropic process
1 point
A heat engine receives heat at a rate of 2 kW from a reservoir maintained at 1000 K and rejects
1 kW to another reservoir maintained at 300 K. If the engine produces 1.2 kW of power, then

it satisfies both first & second laws of thermodynamics.

it satisfies the first law of thermodynamics, but violates the second law.
it satisfies the second law of thermodynamics, but violates the first law.
it violates both first & second laws of thermodynamics.
1 point
Among the following statements, which one is FALSE for a closed system undergoing an
irreversible process?

Its entropy always increases during a heating process.

Its entropy always decreases during a cooling process
Its entropy can decrease or increase during a cooling process, depending on the
magnitude of heat transfer involved.
Its entropy always increases during an adiabatic process.
1 point
A system is maintained at a temperature lower than its immediate surrounding. Its exergy is

positive
negative
zero
undefined
1 point
Irreversibility for a heat pump can be defined as

reversible work – useful work

useful work – reversible work
 useful work – surrounding work
actual work – surrounding work
Nitrogen enters a diffuser at 100 kPa, 300 K, with a velocity of 250 m/s and the exit velocity is
25 m/s. If nitrogen can be considered as an ideal gas with cp=1.042cp=1.042 kJ/kg.K, the exit
temperature (correct to 1 decimal place) is _________________ K.
Hint

1 point
A gas of mass 1.5 kg undergoes a quasi-static expansion, which follows a relationship
p=a+bv, where a and b are constants. The initial and final pressures are 1000 kPa and 200 kPa
respectively, and corresponding volumes are 0.2 m3 and 1.2 m3. The specific internal energy of
the gas is given by the relation, u=1.5pv-85 kJ/kg. Here p is in kPa and v is in m3/kg.m3/kg.. Then
the net heat transfer associated with this process (correct to 1 decimal place) is
___________________ kJ.
Hint

1 point
Air is expanded from 2000 kPa, 500°C, to 100 kPa, 50°C. If air can be assumed to be an ideal
gas with constant isobaric specific heat of 1.04 kJ/kg.K, then the change in specific entropy of
air during the process (correct to 1 decimal place) is ___________ J/kg.K
Hint

1 point
An air compressor is used to charge an initially-empty tank of 200 litre volume, with air up to 5
MPa. The air inlet to the compressor is at 100 kPa, 17 °C, and the isentropic efficiency of the
compressor is 80%. If air can be considered to be an ideal gas with constant properties, then
the total compressor work requirement (correct to 2 decimal places) is ___________________
MJ.
Hint

1 point
Air flows into a heat engine at ambient conditions of 100 kPa, 300 K. Energy is supplied as 1200
kJ per kg of air flow, from a source maintained at 1500 K. During the process, system suffers a
heat loss of 300 kJ per kg of air at 750 K. If the air leaves the engine at 100 kPa, 800 K, then
the second law efficiency (correct to 1 decimal place) __________ %.
Hint

1 point
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Assignment 2
Due date: 2019-08-14, 23:59 IST.
Assignment not submitted
1 point
Isothermal compressibility is defined as

−v(∂p∂v)T−v(∂p∂v)T

v(∂p∂v)Tv(∂p∂v)T

1v(∂p∂v)T1v(∂p∂v)T
−1v(∂p∂v)T−1v(∂p∂v)T
1 point
For a particular substance, if represents isothermal compressibility and represents volume
expansivity, then, among the following relations, which one is true?

β=α(∂T∂P)vβ=α(∂T∂P)v

β=α(∂P∂T)vβ=α(∂P∂T)v

β=α(∂v∂P)Tβ=α(∂v∂P)T

β=α(∂P∂v)Tβ=α(∂P∂v)T
1 point
Consider a sample of air maintained at 300 K and 0.75 kg/m . Treating air as an ideal gas with
3

R = 0.287 kJ/kg.K, the change in pressure of the sample for 1% increase in specific volume at
constant temperature is

– 2.873 kPa
– 1.339 kPa
zero
2.873 kPa
1 point
A particular gas substance follows the relation, (p−av2)(v−b)=RT(p−av2)(v−b)=RT. Using the Maxwell
relations, find (∂s∂v)T(∂s∂v)T =

Rv−bRv−b

aRv−baRv−b

P−av−bP−av−b

RbRb

1 point
Joule-Thomson coefficient for an ideal gas is

positive
negative
zero
undefined
1 point
A substance can be used as a refrigerant when
 its temperature is greater than the maximum inversion temperature and the Joule-Thomson
coefficient is positive.
its temperature is greater than the maximum inversion temperature and the Joule-Thomson
coefficient is negative.
its temperature is lesser than the maximum inversion temperature and the Joule-Thomson
coefficient is positive.
its temperature is lesser than the maximum inversion temperature and the Joule-Thomson
coefficient is negative.
1 point
Among the followings, which conclusion can be drawn from the Mayer relation?

Isobaric specific heat is always greater than isochoric specific heat.

Difference between isobaric and isochoric specific heats vanishes at absolute zero
temperature.
Both specific heats are identical for a purely incompressible substance.
All of the above.
A fixed quantity of Helium at 100 kPa, 293 K, is taken to 600 kPa, 573 K, during a particular
process. Helium follows the relation P(v-b) = RT. If, for
Helium, Cp=5.1926kJ/kgKCp=5.1926kJ/kgK and R=2.0769kJ/KgKR=2.0769kJ/KgK, then the change in specific
entropy during the process (correct to 1 decimal place) is ___________________ J/kg.K.
Hint

1 point
During a particular heating process, temperature of air increases from 20°C to 300°C. Air is
found to follow the relation P(v−b)=RTP(v−b)=RT. If air can be assumed to have constant value of
isochoric specific heat (Cv)=0.731kJ/kgK(Cv)=0.731kJ/kgK, then the change in specific internal energy
during the process (correct to 1 decimal place) is ___________________ kJ/kg.
Hint

1 point
Saturation temperatures for steam at 275 kPa, 300 kPa & 325 kPa are 130.58°C, 133.52°C and
136.27°C, respectively. If the change in specific volume during the phase change process at
300 kPa is 0.60475 m /kg, then the enthalpy change associated with this phase change at 300
3

kPa (correct to 1 decimal place) is _______________ kJ/kg.

Hint

1 point
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Hmt

Assignment 1
Due date: 2019-08-14, 23:59 IST.
Assignment not submitted
1 point
First law of thermodynamics introduces the concept of which thermodynamic property?

(a) internal energy

 (b) total energy

(c) enthalpy

(d) entropy

1 point
Among the following parameters, which one is a vector quantity?

(a) temperature

(b) heat

(c) heat rate

(d) heat flux

1 point
Among the followings, which one is not a property of the system alone?

(a) thermal conductivity

(b) convective heat transfer coefficient

(c) emissivity

(d) heat capacity

1 point
Among the following parameters, the amount of thermal energy emitted by a real surface during radiation heat transfer does not depend on
which one?

(a) specific heat

(b) surface temperature

(c) emissivity

(d) surface area

A concrete slab of 11 m length, 8 m width and 0.2 m thickness, is experiencing temperatures of 17°C & 10°C in its top and bottom surface
respectively. If concrete has a thermal conductivity of 1.4 W/m.K, the rate of heat transfer through the slab (correct to 1 decimal place) is
___________________ kW.

1 point
A freezer assumes the shape of a cubical cavity, which is 2 m on a side. Its inner and outer surface temperatures are –10 and 35°C
respectively, while the bottom of the chamber is ideally insulated. A Styrofoam insulation (k = 0.03 W/m.K) is employed on the outer surface. If
the heat leakage needs to be restricted to 500 W, the minimum thickness of insulation required (correct to 1 decimal place) is
___________________ mm.

1 point
A masonry wall having thermal conductivity of 0.75 W/m.K is subjected to the same temperature difference across it, as is the case for a
composite wall having a thermal conductivity of 0.25 W/m.K and thickness of 100 mm. If the heat transfer rate through the masonry wall is
80% of the other one, then its thickness (correct to 1 decimal place) is ___________________ cm.

1 point
Air at 40°C flows over a long, 25-mm diameter cylinder with an embedded heater. To maintain a surface temperature of 300°C, if 450 W of
heater power per unit length of the cylinder is required, then corresponding heat transfer coefficient (correct to 1 decimal place) is
___________________ W/m2.K.

1 point
A square isothermal chip of 5 mm width is mounted on a substrate such that its side and back surfaces are ideally insulated. The front
surface is exposed to the flow of a coolant with temperature of 15°C. Corresponding convective heat transfer coefficient is 200 W/m 2.K. If the
chip temperature has to be restricted to 85°C, then the maximum allowable chip power (correct to 2 decimal places) is _________________ W.

1 point
A spherical probe of 0.8 m diameter is placed in the space, while it dissipates 150 W of power. Probe surface has an emissivity of 0.8. If the
probe is not receiving energy from any other source, then its surface temperature (correct to 1 decimal place) is ___________ K.

1 point
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Assignment 2
Due date: 2019-08-14, 23:59 IST.
Assignment not submitted
1 point
The primary mechanism of energy transmission via conduction through a non-conducting solid
is.

molecular collision
lattice vibration

molecular diffusion
transmission of free electrons
1 point
According to the Fourier’s law, the direction of conduction heat transfer is always.

normal to an isothermal surface.

tangential to an isothermal surface.

dependent on the thermal conductivity of the material.
dependent on the thermal diffusivity of the material.
1 point
Thermal diffusivity is defined as the ratio of.

thermal conductivity to specific heat

thermal conductivity to kinematic viscosity
thermal conductivity to volumetric heat capacity

thermal conductivity to dynamic viscosity

1 point
For a steady-state 1-D heat conduction scenario, at the absence of any internal heat generation,

heat flux remains constant for any geometry

heat rate remains constant for any geometry

heat rate changes for a cylinder

heat flux remains constant for a sphere
1 point
In a heat transfer problem, the boundary condition of the third kind refers to

a specified value of temperature at the boundary

a specified value of temperature gradient at the boundary

a combination of temperature and temperature gradient specified at the boundary

zero heat flux at the boundary

1 point
Among the followings, which one has the largest thermal conductivity?

silver
copper
aluminum
stainless steel
1 point
Among the followings, which one has the least thermal conductivity?

common wood
glass fibre
aluminium foil
typical silica power
Consider a plane wall of 100 mm thickness and 100 W/m.K thermal conductivity. If its left and
right surfaces are maintained at temperatures of 400 K and 600 K respectively, then the heat
flux at the right wall is ___________________ K/m.
Hint

1 point
A pipeline of 1 m length and 0.005 m cross-sectional area is made of material having thermal
2

conductivity of 25 W/m.K. Under normal operating conditions, the temperature variation along
the length of the pipe can be presented as, T(x)=100 - 150x + 10x , while the variation in the 2

radial direction can be neglected. Then the conduction heat rate at x= 1 m (correct to 1 decimal
place) is ___________________ W.

Hint

1 point
The steady-state temperature distribution in a 1-D wall of thermal conductivity 50 W/m.K and thickness 50 mm is observed to
be T(°C)=a+bx where a= 200°C, b= -2000°C/m , and x is in meter. Then the rate of heat
2

generation within the wall(correct to 1 decimal place) is ___________________ MW/m . 3

Hint

1 point
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ssignment No. 1
Due date: 2019-08-14, 23:59 IST.
Assignment not submitted
1 point

Manufacturing is a process of converting raw material of

Low value to high value

High value to low value

No value change

All of the above

1 point
Miniaturization is primarily concerned with
 Increase in the effectiveness of the product

Compactness of the product

Maximum utilization of the product

Minimum utilization of the product

1 point
Hardening during sheet metal forming of carbon steel primarily occurs due to

Work hardening

Precipitate hardening

Solid solution strengthening

Transformation hardening

1 point
The process best in terms of close control of tolerance and surface finish is

Casting

Forming

Joining

Machining

1 point
The process generally preferred for manufacturing of wheels and pulleys is

Rolling

Casting

Machining

Extrusion

1 point
Castability is poor for

High melting point material

Low melting point material

Ductile material

All of the above

1 point

Solidification temperature range is shown by

Pure metals

Eutectic alloy

Other than eutectic alloy

All of the above

1 point

Machinability of the material, that are machined by the conventional method is poor for the
 Low hardness materials (~10 HRC)

High hardness materials (~65 HRC)

Low strength materials (200 MPa)

Ductile materials (10% elongation)

1 point
Manual intervention in the machine system is minimum for

Semi-automatic machine

Conventional machine

Fully automatic machine

All of the above

1 point

Lean manufacturing is based on

CNC connected system

Rapid prototyping

Inventory strategy

Reducing waste

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Assignment No. 2
Due date: 2019-08-14, 23:59 IST.
Assignment not submitted
1 point
The metals which can be machined by non-conventional method is/are

Ceramics

Titanium alloy

Super alloys

All of the above

1 point
Parameters primarily considered for selection of a manufacturing process for a given product are

Product features and operational cost

Roughness and tolerance

Flatness and accuracy

All of the above

1 point
Primary shape of large size components like Girth gear, large diameter shaft etc. is realized through

Forming
 Casting

Joining

Machining

1 point
Hand tools like wrenches, spanner and hammer etc. are made by the process of

Casting

Forging

Machining

Rolling

1 point
Transformation hardening in high carbon steels due to heating and cooling cycle is caused by

Precipitates

Change of phase

Dislocation

Second phase particles

1 point
Dissolution of precipitates due to external heating of precipitation hardened Al alloy is known as

Dissolution

Reversion

Recreation

All of the above

1 point
A component can be produced by any of the four processes I, II, III, IV. The fixed cost and the variable cost for each of the processes are
tabulated below. The most economical process for producing a batch of 100 pieces is

II

III

IV

1 point
In a small scale industry, for manufacturing a product the fixed cost is Rs. 5000. The variable cost is Rs. 20 per product and sales price is Rs.
30 per product. The break-even production will be

300

460

500
 10000

1 point
Sand casted product are characterized as

High tolerance limit and poor surface finish

Low tolerance limit and good surface finish

Low tolerance limit and poor surface finish

High tolerance limit and good surface finish

1 point
Metal having higher specific heat generally offers

Lower fluidity

Higher fluidity

Moderate fluidity

Can’t relate to fluidity

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Assignment 0
Due date: 2019-08-31, 23:59 IST.
Assignment not submitted
1 point
Among the followings, which one is not a thermodynamic property?

(A) Mass

(B) Entropy

(C) Specific heat

(D) Force

1 point
Among the following properties, which one is defined by the first law of thermodynamics?

(A) Temperature

(B) Total energy

(C) Entropy

(D) Exergy

1 point
Among the following scenarios, identify the one which involves an isolated system.

(A) A domestic water heat under switched on condition

(B) A rooftop water tank open to solar radiation, with all valves closed

(C) A mobile phone under charging condition

(D) A sealed bottle of water at 0°C, kept within blocks of ice at the same temperature

1 point
A reversible refrigerator and a reversible heat pump is working with the same temperature limits. Then, among the followings, which
statement is true about their performance?

(A) COPHP = 1 + COPR

(B) COPR = 1 + COPHP

(C) COPHP = 1 - COPR

(D) COPHP = COPR

Heat is transferred to a heat engine from a furnace at a rate of 80 MW. If the rate of waste heat rejection to the nearby river is 50 MW, the
percentage thermal efficiency of the engine (correct to 1 decimal place) ___________.

1 point

The temperature t on a thermometric scale is defined in terms of a property K by the relation

t=a ln⁡K+b
where a and b are constants. The values of K are found to be 1.83 and 6.78 at the ice point and
the steam point, the temperatures of which are assigned the numbers 0 and 100, respectively.
Then the temperature corresponding to a reading of K equal to 2.42 on the thermometer (correct
to 2 decimal places) is _________________.
1 point

A mass of gas is compressed in a quasi-static process from 80 kPa, 0.1 m , to 0.4 MPa, 3

0.03 m . If the pressure and volume are related by pv = constant, the work done on the
3 n

system (correct to 2 decimal places) is ___________________ kJ.

1 point
Air flows steadily at a rate of 0.5 kg/s through an air compressor, entering with 7 m/s velocity, 100 kPa pressure and 0.95 m /kg volume, and leaving
3

with 5 m/s, 700 kPa and 0.19 m /kg respectively. Internal energy of air leaving is 90 kJ/kg greater than that of air entering. If the cooling water in the
3

compressor jackets absorb heat from the air at a rate of 58 kW, the rate of shaft work input to air (correct to 1 decimal place) is ___________ kW.
1 point

Two streams of air, one at 1 bar, 27 °C and velocity of 30 m/s, and the other at 5 bar,
227 °C and velocity of 50 m/s, mix in equal proportion in a chamber, from which heat is
removed at the rate of 100 kJ/kg. The mixture then passes through an adiabatic nozzle
and leaves that with a temperature of 27 °C. If air can be treated as an ideal gas
C with = 1.005 kJ/kg.K, the velocity of air stream coming out of the nozzle (correct to 1
p

decimal place) is _____________ m/s.

1 point
A heat engine receives 5 kW of heat from a source at 800 K and 10 kW from another at 1000 K, while rejecting heat to a reservoir at 600 K. If the process can be assumed to be
reversible, the power output from the engine (correct to 1 decimal place) __________ kW.

1 point
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Assignment 0
The due date for submitting this assignment has passed.

Due on 2019-08-04, 23:59 IST.

As per our records you have not submitted this assignment.

1 point

SI unit of temperature is Kelvin (K). 1 K is defined as a certain fraction of which particular

temperature?
 melting point of lead

critical point of ammonia

normal boiling point of mercury

triple point of water

No, the answer is incorrect.
Score: 0
Accepted Answers:

triple point of water

1 point

The concept of temperature can be obtained from the

zeroth law of thermodynamics

first law of thermodynamics

second law of thermodynamics

third law of thermodynamics

No, the answer is incorrect.
Score: 0
Accepted Answers:

zeroth law of thermodynamics

1 point

Rankine scale is the absolute version of the conventional Fahrenheit temperature scale. The
absolute zero in the Rankine (R) scale is marked as

– 459.67 R

– 273.15 R

0R

459.67 R
No, the answer is incorrect.
Score: 0
Accepted Answers:

0R
1 point
Which among the following metal combinations is referred to K-type thermocouple?

Copper-Constantan

Chromel-Alumel

Iron-Constantan

Chromel-Constantan
No, the answer is incorrect.
Score: 0
Accepted Answers:

Chromel-Alumel
1 point

Based on its dynamic characteristics, a mercury-filled liquid-in-glass thermometer can be

identified as a

zeroth-order instrument

first-order instrument

second-order instrument

third-order instrument
No, the answer is incorrect.
Score: 0
Accepted Answers:

first-order instrument
1 point

Replacing mercury by mercury-thallium mixture as the thermometric fluid in a liquid-in-glass

thermometer helps in

reducing the lowest temperature possible to be measured

increasing the highest temperature possible to be measured

reducing the toxicity level

enhancing the visibility of liquid column inside capillary tube

No, the answer is incorrect.
Score: 0
Accepted Answers:

reducing the lowest temperature possible to be measured

1 point

RTD is a common instrument used for precise temperature measurement. The full-form of the
acronym RTD is

resistance thermal display

resistance thermal detector

resistance temperature display

resistance temperature detector

No, the answer is incorrect.
Score: 0
Accepted Answers:

resistance temperature detector

A conventional medical thermometer records the body temperature of a person to be 99.7. Then
the temperature in Celsius scale (correct to 1 decimal place) is __________ °C.
Hint

No, the answer is incorrect.

Score: 0
Accepted Answers:
(Type: Range) 37.5,37.7

1 point

The temperature tt on a thermometric scale is defined in terms of a property KK by the

relation t=alnK+bt=aln⁡K+b
where aa and bb are constants. The values of KK are found to be 1.83 and 6.78 at the ice point
and the steam point, the temperatures of which are assigned the numbers 0 and 100,
respectively. Then the temperature corresponding to a reading of KK equal to 2.42 on the
thermometer (correct to 2 decimal places) is _________________.

Hint

No, the answer is incorrect.

Score: 0
Accepted Answers:
(Type: Range) 21.0,21.8

1 point

Air flows steadily at a rate of 0.5 kg/s through an air compressor, entering with 7 m/s velocity,
100 kPa pressure and 0.95 m /kg volume, and leaving with 5 m/s, 700 kPa and 0.19 m /kg
3 3

respectively. Internal energy of air leaving is 90 kJ/kg greater than that of air entering. If the
cooling water in the compressor jackets absorb heat from the air at a rate of 58 kW, the rate of
shaft work input to air (correct to 1 decimal place) is ___________ kW.
Hint
No, the answer is incorrect.
Score: 0
Accepted Answers:
(Type: Range) 115,128

Assignment No. 0
Due date: 2019-08-31, 23:59 IST.
Assignment not submitted
1 point
Stress is

Load per unit length

Pressure per unit area

Load per unit area

Change in length per unit length

1 point
Strain is

Change in length

Change in length per unit length

Load per unit length

Stress×Area

1 point
The result of a tensile test is generally represented by

Stress-strain curve

Temperature-strain curve

Toughness-temperature curve

Toughness-Hardness curve

1 point
Steels are alloys of

Nickel and copper

Iron and Carbon

Copper and Tin

Titanium and Nickel

1 point
Some grades of steels are called stainless steels due to their

Higher strength

Better corrosion resistance

High hardness

High toughness

1 point
Which one of the following is the oldest manufacturing technique?
 Casting

Ultrasonic machining

3D printing

Electron beam welding

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