MCQs on Guest’s Theory of Failure

1. Guest’s Theory of Failure is also known as: a) Maximum Normal Stress Theory
b) Maximum Strain Energy Theory
c) Maximum Shear Stress Theory
d) Distortion Energy Theory

Answer: c) Maximum Shear Stress Theory

2. Guest’s Theory of Failure assumes failure occurs when: a) The maximum shear stress in a
material exceeds its yield strength in tension.
b) The maximum shear stress in a material exceeds its shear strength.
c) The maximum normal stress exceeds the ultimate tensile stress.
d) The strain energy density exceeds the critical value.

Answer: b) The maximum shear stress in a material exceeds its shear strength.

3. Maximum Shear Stress Theory is primarily used for: a) Ductile materials

b) Brittle materials
c) Both ductile and brittle materials
d) Composites

Answer: a) Ductile materials

4. Guest’s Theory of Failure considers which type of stress?

a) Normal stress
b) Shear stress
c) Principal stress
d) Von Mises stress

Answer: b) Shear stress

5. What is the relationship between yield strength in shear (SsS_sSs) and yield strength in
tension (StS_tSt) according to Maximum Shear Stress Theory?
a) Ss=StS_s = S_tSs=St
b) Ss=0.5⋅StS_s = 0.5 \cdot S_tSs=0.5⋅St
c) Ss=0.577⋅StS_s = 0.577 \cdot S_tSs=0.577⋅St
d) Ss=2⋅StS_s = 2 \cdot S_tSs=2⋅St

Answer: b) Ss=0.5⋅StS_s = 0.5 \cdot S_tSs=0.5⋅St

6. Which principal stresses are considered for Guest’s Theory of Failure?

a) The largest principal stress only
b) The difference between maximum and minimum principal stresses
c) The smallest principal stress only
d) The sum of principal stresses

Answer: b) The difference between maximum and minimum principal stresses

7. Guest’s Theory of Failure is unsuitable for: a) Mild steel

b) Ductile materials
c) Brittle materials
d) Copper
Answer: c) Brittle materials

8. The condition for failure in Maximum Shear Stress Theory is: a) τmax=St\tau_{max} =
S_tτmax=St
b) τmax=Ss\tau_{max} = S_sτmax=Ss
c) τmax≥Ss\tau_{max} \geq S_sτmax≥Ss
d) τmax≥St\tau_{max} \geq S_tτmax≥St

Answer: c) τmax≥Ss\tau_{max} \geq S_sτmax≥Ss

9. What is the formula for maximum shear stress under biaxial loading conditions?
a) τmax=(σ1+σ2)2\tau_{max} = \frac{(\sigma_1 + \sigma_2)}{2}τmax=2(σ1+σ2)
b) τmax=∣σ1−σ2∣2\tau_{max} = \frac{|\sigma_1 - \sigma_2|}{2}τmax=2∣σ1−σ2∣
c) τmax=(σ1−σ2)\tau_{max} = (\sigma_1 - \sigma_2)τmax=(σ1−σ2)
d) τmax=σ1⋅σ2\tau_{max} = \sigma_1 \cdot \sigma_2τmax=σ1⋅σ2

Answer: b) τmax=∣σ1−σ2∣2\tau_{max} = \frac{|\sigma_1 - \sigma_2|}{2}τmax=2∣σ1−σ2∣

10. Which of the following is true about Guest’s Theory?

a) It applies to all materials.
b) It provides conservative results for ductile materials.
c) It overestimates safety for brittle materials.
d) Both b and c

Answer: d) Both b and c

11. For a pure torsion condition, the maximum shear stress is equal to:
a) Maximum normal stress
b) Shear yield strength of the material
c) Half the shear yield strength
d) None of the above

Answer: b) Shear yield strength of the material

12. Guest’s Theory of Failure is based on which property of the material?

a) Yield strength
b) Elastic modulus
c) Poisson’s ratio
d) Hardness

Answer: a) Yield strength

13. Which of the following stress conditions can lead to failure under Guest’s Theory?
a) Hydrostatic stress
b) Pure shear stress
c) Pure compressive stress
d) All of the above

Answer: b) Pure shear stress

14. The principal stress difference (σ1−σ2\sigma_1 - \sigma_2σ1−σ2) in Guest’s Theory is

related to:
a) Axial stress only
b) Maximum strain
 c) Maximum shear stress
d) Tensile stress

Answer: c) Maximum shear stress

15. Guest’s Theory is most applicable for materials exhibiting:

a) High ductility
b) High brittleness
c) Perfect elasticity
d) Large thermal expansion

Answer: a) High ductility

h a list of 15 competitive exam MCQ questions related to Poisson's Ratio:

1. What does Poisson’s ratio measure?

a) Stress in one direction
b) Strain in one direction
c) Lateral strain to axial strain
d) Axial strain to lateral strain
Answer: c

2. For most engineering materials, Poisson’s ratio lies between:

a) 0.2 to 0.3
b) 0.1 to 0.2
c) 0.3 to 0.5
d) 0.5 to 1.0
Answer: a

3. Poisson's ratio is the ratio of:

a) Axial stress to axial strain
b) Shear stress to shear strain
c) Lateral strain to longitudinal strain
d) Longitudinal strain to lateral strain
Answer: c

4. For a perfectly incompressible material, the Poisson’s ratio is:

a) 0
b) 0.5
c) 1
d) Infinity
Answer: b

5. The Poisson's ratio of rubber is approximately:

a) 0.1
b) 0.3
c) 0.5
d) 1
Answer: c
6. If a material has a Poisson's ratio of 0.25, it means:
a) It is incompressible
b) Lateral strain is 25% of axial strain
c) Axial strain is 25% of lateral strain
d) Material has no lateral strain
Answer: b

7. What is the maximum value of Poisson’s ratio for stable materials under elastic
deformation?
a) 0.25
b) 0.5
c) 1.0
d) 0.75
Answer: b

8. If the Poisson’s ratio of a material is 0.5, it indicates the material is:

a) Brittle
b) Elastic
c) Perfectly incompressible
d) Perfectly compressible
Answer: c

9. For structural steel, the approximate value of Poisson’s ratio is:

a) 0.1
b) 0.25
c) 0.3
d) 0.4
Answer: c

10. The Poisson's ratio for concrete typically varies between:

a) 0.1 to 0.2
b) 0.2 to 0.3
c) 0.3 to 0.4
d) 0.4 to 0.5
Answer: b

11. A negative Poisson's ratio implies:

a) Material expands in all directions when stretched
b) Material contracts laterally when stretched
c) Material contracts in all directions when stretched
d) None of the above
Answer: a

12. Which of the following has a negative Poisson’s ratio?

a) Steel
b) Rubber
c) Cork
d) Auxetic materials
Answer: d
 13. Poisson’s ratio affects which of the following properties of materials?
a) Modulus of elasticity
b) Shear modulus
c) Bulk modulus
d) All of the above
Answer: d

14. If Poisson’s ratio is 0, the material is:

a) Perfectly incompressible
b) Compressible with no lateral strain
c) Elastic and incompressible
d) Brittle
Answer: b

15. Which of the following materials has a Poisson’s ratio close to 0?

a) Rubber
b) Cork
c) Steel
d) Lead
Answer: b

Here’s a list of 15 important multiple-choice questions (MCQs) related to ergonomics, useful for
competitive exams:

MCQs on Ergonomics:

1. What is ergonomics primarily concerned with?

a) Designing workstations to enhance aesthetics
b) Ensuring proper equipment maintenance
c) Fitting the job to the worker
d) Increasing organizational hierarchy

Answer: c) Fitting the job to the worker

2. Which of the following is a primary goal of ergonomics?

a) Reduce employee wages
b) Enhance safety and efficiency
c) Automate all manual tasks
d) Replace workers with robots

Answer: b) Enhance safety and efficiency

3. What is the term used to describe injuries caused by repetitive motion?

a) Acute injuries
b) Repetitive Strain Injuries (RSIs)
c) Stress fractures
d) Ergonomic disorders

Answer: b) Repetitive Strain Injuries (RSIs)

4. Which of the following is a principle of ergonomic design?

a) Standardizing all equipment sizes
b) Designing for the average person
 c) Accommodating a wide range of users
d) Reducing the cost of equipment

Answer: c) Accommodating a wide range of users

5. What is the ideal position for a computer monitor according to ergonomic standards?
a) At knee height
b) Slightly above eye level
c) At eye level
d) Slightly below eye level

Answer: d) Slightly below eye level

6. Which of the following tools is commonly used to evaluate ergonomic risks?

a) PERT chart
b) RULA (Rapid Upper Limb Assessment)
c) Gantt chart
d) SWOT analysis

Answer: b) RULA (Rapid Upper Limb Assessment)

7. What does the term "anthropometry" refer to in ergonomics?

a) Study of body measurements and dimensions
b) Study of psychological behavior in workplaces
c) Study of mechanical equipment design
d) Study of environmental factors

Answer: a) Study of body measurements and dimensions

8. Which body part is most affected by poor ergonomic design in workplaces?

a) Legs
b) Spine
c) Arms
d) Feet

Answer: b) Spine

9. What does the "WMSD" in ergonomics stand for?

a) Workstation Maintenance System Design
b) Work-related Musculoskeletal Disorders
c) Workplace Management System Development
d) Workforce Management and Safety Division

Answer: b) Work-related Musculoskeletal Disorders

10. Which of the following factors does NOT directly affect workplace ergonomics?
a) Lighting
b) Ventilation
c) Salary structure
d) Workstation design

Answer: c) Salary structure

 11. In ergonomics, what is the optimal seating posture?
a) Leaning forward with arms extended
b) Sitting upright with a 90-degree angle at hips and knees
c) Reclined at 120 degrees
d) Slouching with knees higher than hips

Answer: b) Sitting upright with a 90-degree angle at hips and knees

12. Which type of grip is ergonomically preferred for tools?

a) Power grip
b) Pinch grip
c) Claw grip
d) Loose grip

Answer: a) Power grip

13. What is "cognitive ergonomics" concerned with?

a) Optimizing mechanical tools
b) Improving mental processes in human-machine interaction
c) Reducing physical strain
d) Enhancing visual design

Answer: b) Improving mental processes in human-machine interaction

14. Which of the following workplace conditions can lead to ergonomic hazards?
a) Adjustable workstations
b) Poor lighting and ventilation
c) Use of ergonomically designed furniture
d) Implementation of regular breaks

Answer: b) Poor lighting and ventilation

15. What does the "OWAS" method in ergonomics stand for?

a) Optimal Workplace Assessment System
b) Occupational Workload Analysis System
c) Ovako Working Posture Analysis System
d) Organized Workplace Alignment System

Answer: c) Ovako Working Posture Analysis System

Ergonomics: The study of designing work environments to fit the physical and cognitive needs of
workers for comfort, safety, and efficiency.

Bauschinger Effect: The phenomenon where a material's yield strength decreases in the opposite
direction of a prior plastic deformation.

Poisson's Effect: The tendency of a material to expand or contract in directions perpendicular to

the applied force during stretching or compression.

Work Hardening: The strengthening of a material through plastic deformation, increasing its
resistance to further deformation.

Stress Recovery: The process by which a material partially or fully returns to its original state after
the removal of applied stress.
Here are 15 important competitive exam multiple-choice questions (MCQs) related to the Steady
Flow Energy Equation (SFEE):

1. What is the Steady Flow Energy Equation primarily used for?

A) Calculating heat transfer in closed systems

B) Energy analysis in open systems
C) Determining thermal stresses
D) Analyzing transient processes
Answer: B

2. Which of the following is NOT an assumption for applying the Steady Flow Energy Equation?

A) The flow is steady

B) The mass flow rate is constant
C) There is no energy loss
D) Energy transfer through work, heat, and mass can occur
Answer: C

3. In the Steady Flow Energy Equation, which form of energy is NOT considered?

A) Potential energy
B) Kinetic energy
C) Chemical energy
D) Flow work
Answer: C

4. Which of the following devices typically operates under the assumptions of SFEE?

A) Heat exchanger
B) Turbine
C) Compressor
D) All of the above
Answer: D

5. What is "flow work" in the context of SFEE?

A) The work required to rotate the system

B) The work done by the fluid to enter or exit the system
C) Heat transfer due to conduction
D) None of the above
Answer: B
6. The SFEE includes which type of energy terms?

A) Internal, kinetic, and potential energy

B) Internal, thermal, and electrical energy
C) Kinetic, potential, and radiant energy
D) Potential, elastic, and magnetic energy
Answer: A

7. Which of the following is true for the Steady Flow Energy Equation?

A) Inlet energy = Outlet energy

B) Inlet energy + Heat added = Outlet energy + Work done
C) Heat added = Work done
D) None of the above
Answer: B

8. In an ideal nozzle, what is the primary energy transformation?

A) Heat to kinetic energy

B) Potential energy to internal energy
C) Enthalpy to kinetic energy
D) Internal energy to potential energy
Answer: C

9. Which term is neglected in SFEE for a throttling process?

A) Enthalpy
B) Work transfer
C) Kinetic energy
D) Potential energy
Answer: B

10. For an ideal turbine, which assumption is correct in SFEE?

A) Heat transfer is negligible

B) Work output is zero
C) Velocity change is negligible
D) Enthalpy remains constant
Answer: A

11. The specific energy of a fluid at any point in an open system is expressed as a function of:

A) Pressure, temperature, and enthalpy

B) Enthalpy, velocity, and height
C) Pressure, velocity, and internal energy
D) Density, velocity, and height
Answer: B

12. In a heat exchanger, the SFEE assumes that:

A) The work transfer is zero

B) The heat transfer is zero
C) The mass flow rate is constant
D) Both A and C
Answer: D

13. The Steady Flow Energy Equation is most applicable to which of the following devices?

A) Cylinders
B) Valves
C) Open systems like turbines and nozzles
D) Closed systems like pistons
Answer: C

14. The term v22\frac{v^2}{2}2v2 in the SFEE represents which energy form?

A) Kinetic energy
B) Potential energy
C) Flow work
D) Internal energy
Answer: A

15. When analyzing an open system using SFEE, the mass flow rate is:

A) Variable at inlet and outlet

B) Zero at both inlet and outlet
C) Equal at inlet and outlet
D) Dependent on temperature
Answer: C

Dalton's Law of Partial Pressures states that in a mixture of non-reacting gases, the total pressure
exerted by the mixture is equal to the sum of the partial pressures of each individual gas.

Mathematically:
Ptotal=P1+P2+P3+⋯+PnP_{\text{total}} = P_1 + P_2 + P_3 + \dots + P_nPtotal=P1+P2+P3+⋯+Pn

Where:

• PtotalP_{\text{total}}Ptotal: Total pressure of the gas mixture

• P1,P2,P3,…P_1, P_2, P_3, \dotsP1,P2,P3,…: Partial pressures of individual gases

Each gas behaves as if it occupies the entire volume of the container alone, regardless of the
presence of other gases.

Here are 15 important multiple-choice questions (MCQs) related to diesel engines for competitive
exams:

1. Which of the following is the main function of a diesel engine’s fuel injector? a) To
compress the air-fuel mixture
b) To atomize and inject fuel into the combustion chamber
c) To monitor exhaust emissions
d) To cool the engine
Answer: b) To atomize and inject fuel into the combustion chamber

2. The ratio of the volume of air in the cylinder when the piston is at the bottom of the stroke
to the volume when the piston is at the top of the stroke is called the: a) Stroke ratio
b) Compression ratio
c) Torque ratio
d) Power ratio
Answer: b) Compression ratio

3. Which type of combustion system is commonly used in modern diesel engines? a) Spark
ignition system
b) Compression ignition system
c) Pre-chamber system
d) Rotary combustion system
Answer: b) Compression ignition system

4. The term "knocking" in a diesel engine is caused by: a) Low compression ratio
b) Improper fuel injection timing
c) High air-fuel mixture ratio
d) Higher engine temperature
Answer: b) Improper fuel injection timing

5. In diesel engines, which of the following is used to cool the exhaust gases? a) Water cooling
b) Air cooling
c) EGR (Exhaust Gas Recirculation)
d) Turbocharging
Answer: c) EGR (Exhaust Gas Recirculation)

6. The primary purpose of a turbocharger in a diesel engine is to: a) Increase fuel consumption
b) Increase engine exhaust temperature
c) Increase engine power by compressing intake air
d) Reduce noise
Answer: c) Increase engine power by compressing intake air

7. Which of the following is an essential feature of a diesel engine over a gasoline engine? a)
Use of spark plugs for ignition
b) Higher compression ratio
c) Simpler fuel injection system
d) Lower torque output
Answer: b) Higher compression ratio
8. The diesel engine requires which of the following for combustion? a) A spark plug
b) Compressed air and fuel
c) A glow plug
d) A carburetor
Answer: b) Compressed air and fuel

9. What is the function of the governor in a diesel engine? a) To control exhaust emission
b) To regulate engine speed
c) To inject fuel into the combustion chamber
d) To increase engine torque
Answer: b) To regulate engine speed

10. Which of the following types of fuel is commonly used in diesel engines? a) Ethanol
b) Petrol
c) Diesel
d) Compressed natural gas
Answer: c) Diesel

11. In a diesel engine, what does the term "scavenging" refer to? a) Removing carbon deposits
from the engine
b) Removing exhaust gases from the cylinder
c) Increasing the air-fuel mixture ratio
d) Reducing fuel consumption
Answer: b) Removing exhaust gases from the cylinder

12. Which of the following engines typically operates at a higher compression ratio? a)
Gasoline engine
b) Diesel engine
c) Rotary engine
d) Stirling engine
Answer: b) Diesel engine

13. Which component is responsible for mixing the air and fuel in a diesel engine? a)
Carburetor
b) Fuel injector
c) Spark plug
d) Air filter
Answer: b) Fuel injector

14. What is the main difference between a two-stroke and a four-stroke diesel engine? a) The
number of fuel injectors used
b) The number of strokes in the engine cycle
c) The type of fuel used
d) The presence of a turbocharger
Answer: b) The number of strokes in the engine cycle

15. What is the purpose of a diesel particulate filter (DPF) in modern diesel engines? a) To
increase fuel efficiency
b) To reduce exhaust temperature
c) To reduce particulate emissions
 d) To increase engine power
Answer: c) To reduce particulate emissions

16. • Sensible heat of water: The heat required to raise the temperature of water without
changing its phase.
17. • Latent heat of vaporization: The heat required to convert water into steam at
constant temperature without changing its temperature.
18. • Enthalpy of steam: The total heat content of steam, including both sensible heat
and latent heat.
19. • Entropy of steam: A measure of the disorder or randomness in the steam, related
to heat transfer during phase change.
Specific Weight:

• Definition: The weight per unit volume of a substance.

• Formula: γ=WV\gamma = \frac{W}{V}γ=VW

• Units: N/m3\text{N/m}^3N/m3 (Newton per cubic meter)

Specific Speed:

• Definition: A dimensionless number that describes the type of a pump or turbine based on
its speed, flow, and head.

• Formula: Ns=NQH3/4N_s = \frac{N \sqrt{Q}}{H^{3/4}}Ns=H3/4NQ

• Units: Dimensionless (often denoted in rpm for turbines or pumps)

Specific Gravity:

• Definition: The ratio of the density of a substance to the density of water.

• Formula: SG=ρsubstanceρwaterSG = \frac{\rho_{substance}}{\rho_{water}}SG=ρwater

ρsubstance

• Units: Dimensionless (no units)

Specific Volume:

• Definition: The volume occupied by a unit mass of a substance.

• Formula: v=Vmv = \frac{V}{m}v=mV

• Units: m3/kg\text{m}^3/\text{kg}m3/kg (cubic meters per kilogram)

• • Oblique View: A 2D representation of a 3D object where the front is shown in true

shape, and the depth is represented at an angle (usually 45°). It gives a clear view of
the front, top, and side surfaces.
• • Orthographic View: A 2D representation where multiple views (front, top, side)
are used to show the exact shape and size of an object. Each view is projected at a 90°
angle from the other.
• • Perspective View: A 3D representation that simulates how an object looks to the
human eye, with converging lines and vanishing points. It provides depth and realism,
but distortion occurs with distance.
• • Pictorial View: A 3D visual representation of an object, typically showing three
faces (front, top, and side) in one view, such as in isometric, axonometric, or oblique
projections. It's used to illustrate the object more clearly in one image.

Here are 15 competitive exam-style MCQs related to liquids, with answers:

1. Which of the following is the property of a liquid?

o a) Definite shape and volume

o b) Definite volume but no definite shape

o c) No definite volume and shape

o d) None of the above

Answer: b) Definite volume but no definite shape

2. What is the unit of surface tension?

o a) N/m

o b) N/s

o c) m/s

o d) J/m²
Answer: a) N/m

3. Which of the following has the highest viscosity?

o a) Water

o b) Honey

o c) Alcohol

o d) Air
Answer: b) Honey

4. The force acting on the surface of a liquid which tends to reduce its surface area is called:

o a) Cohesion

o b) Adhesion

o c) Surface tension

o d) Viscosity
Answer: c) Surface tension

5. What is the name of the phenomenon where a liquid rises in a narrow tube against
gravity?

o a) Surface tension
 o b) Capillary action

o c) Viscosity

o d) Diffusion
Answer: b) Capillary action

6. The density of a liquid decreases with:

o a) Increase in temperature

o b) Decrease in temperature

o c) Increase in pressure

o d) No effect on temperature or pressure

Answer: a) Increase in temperature

7. Which of the following liquids has the highest density at 20°C?

o a) Water

o b) Mercury

o c) Alcohol

o d) Glycerin
Answer: b) Mercury

8. Which property of liquids allows them to flow?

o a) Surface tension

o b) Viscosity

o c) Cohesion

o d) Adhesion
Answer: b) Viscosity

9. The angle of contact of a liquid with a solid surface is least for:

o a) Water

o b) Mercury

o c) Alcohol

o d) Oil
Answer: b) Mercury

10. Which of the following liquids will have the highest rate of evaporation?

o a) Water

o b) Alcohol

o c) Glycerin
 o d) Mercury
Answer: b) Alcohol

11. In a liquid, molecules move:

o a) Randomly and freely

o b) In a straight line

o c) In a fixed pattern

o d) In a circular motion
Answer: a) Randomly and freely

12. Which of the following liquids has the lowest surface tension at room temperature?

o a) Water

o b) Mercury

o c) Alcohol

o d) Oil
Answer: c) Alcohol

13. What is the effect of temperature on the viscosity of a liquid?

o a) Viscosity increases with temperature

o b) Viscosity decreases with temperature

o c) Viscosity remains unchanged with temperature

o d) Temperature does not affect viscosity

Answer: b) Viscosity decreases with temperature

14. The principle of buoyancy is based on:

o a) Archimedes' Principle

o b) Pascal's Law

o c) Bernoulli’s Principle

o d) Hooke’s Law
Answer: a) Archimedes' Principle

15. The property of liquids to resist changes in their shape is due to:

o a) Surface tension

o b) Cohesive force

o c) Adhesive force

o d) Viscosity
Answer: b) Cohesive force

Carnot Cycle:
 1. Ideal thermodynamic cycle for heat engines.

2. Consists of two isothermal processes (heat absorption and rejection) and two adiabatic
processes (expansion and compression).

3. Maximum efficiency possible for a heat engine operating between two temperature
reservoirs.

4. Efficiency formula: η=1−TcoldThot\eta = 1 - \frac{T_{cold}}{T_{hot}}η=1−ThotTcold (where

TcoldT_{cold}Tcold and ThotT_{hot}Thot are the absolute temperatures of the cold and hot
reservoirs).

5. It is a reversible cycle, and the engine operates with no increase in entropy.

Stirling Cycle:

1. Closed regenerative thermodynamic cycle, used in Stirling engines.

2. Involves two isothermal processes and two constant-volume processes.

3. Heat is added and rejected at constant temperature, using a working gas (usually helium or
hydrogen).

4. Efficiency approaches the Carnot efficiency but is typically lower in practice.

5. Regenerator stores heat during the compression stroke and returns it during the expansion
stroke, increasing efficiency.

Ericsson Cycle:

1. Similar to the Stirling cycle, with two isothermal processes and two constant-volume
processes.

2. The key difference is that the Ericsson cycle uses external heat sources and is more efficient
in converting heat into work.

3. The cycle operates at constant temperature during both compression and expansion
processes.

4. Typically used in idealized heat engines but less common in real-world applications.

Bell-Coleman Cycle:

1. Ideal refrigeration cycle used in air compressors and refrigerators.

2. Isentropic compression (compression at constant entropy), followed by isochoric cooling

(constant volume).

3. Isentropic expansion (expansion at constant entropy), followed by isochoric heating

(constant volume).

4. Uses air as the working fluid, and the cycle is ideal for low-temperature refrigeration.

5. Commonly referred to as the air refrigeration cycle.

Here are the laws of thermodynamics in point form, relevant for competitive exams:

1. Zeroth Law of Thermodynamics:

 o If two systems are each in thermal equilibrium with a third system, then they are in
thermal equilibrium with each other.

o This law defines temperature and the concept of thermal equilibrium.

2. First Law of Thermodynamics (Law of Energy Conservation):

o Energy cannot be created or destroyed; it can only be transferred or converted from

one form to another.

o The change in internal energy of a system is equal to the heat added to the system
minus the work done by the system.

o Formula: ΔU=Q−W\Delta U = Q - WΔU=Q−W

3. Second Law of Thermodynamics:

o The total entropy of an isolated system always increases over time, approaching a
maximum value at equilibrium.

o Heat cannot spontaneously flow from a colder body to a hotter body.

o Entropy, a measure of disorder, tends to increase in natural processes.

4. Third Law of Thermodynamics:

o As the temperature of a system approaches absolute zero, the entropy of the system
approaches a minimum value (often taken as zero).

o It is impossible to reach absolute zero in a finite number of steps

Here’s the competitive exam-related information on the specified tests:

1. Charpy Test:

o Used to measure the impact toughness of materials.

o A notched specimen is struck by a pendulum to determine the energy absorbed

during fracture.

o Provides information about material’s brittleness or ductility at low temperatures.

2. Knoop Test:

o A microhardness test used for small, thin materials or coatings.

o Uses a diamond indenter with an elongated pyramid shape.

o The indentation size is measured under a microscope to determine hardness.

3. Spiral Test:

o A test used to evaluate the formability of sheet metal under torsion.

o Typically used in automotive and manufacturing industries to study the material's

ability to resist cracking or failure under spiral deformation.

4. Cupping Test:
 o Used to determine the deep drawing ability (formability) of sheet metals.

o A punch is used to deform the metal into a cup shape, and the depth to which it can
be drawn without failure is measured.

o Important in assessing the suitability of metal for forming processes.

Here are brief competitive exam-related points for each material:

1. High-Speed Steel (HSS):

o Used for manufacturing cutting tools like drills, taps, and mills.

o Contains tungsten, molybdenum, chromium, and vanadium.

o High hardness and wear resistance at elevated temperatures.

o Maintains hardness up to 500°C.

o Excellent tool life compared to carbon steels.

2. Hypo-Eutectoid Steel:

o Contains less than 0.8% carbon by weight.

o Consists primarily of ferrite with pearlite.

o Softer and more ductile than eutectoid and hyper-eutectoid steels.

o Used for applications requiring good formability and toughness.

3. Hyper-Eutectoid Steel:

o Contains more than 0.8% carbon by weight.

o Mainly consists of cementite and pearlite.

o Harder and stronger but less ductile than hypo-eutectoid steels.

o Used in applications requiring high wear resistance, such as cutting tools and high-
strength materials.

4. Cast Iron:

o Contains 2-4% carbon, with silicon content between 1-3%.

o Excellent castability and machinability.

o Types include gray cast iron, white cast iron, ductile cast iron, and malleable cast
iron.

o Used in engine blocks, pipes, and heavy machinery due to its wear resistance and
good fluidity during casting.

Here’s a brief description of each term in the context of competitive exams:

1. Metacentre:

o The point where the buoyant force acts on a floating object when it is tilted. It is
crucial in determining the stability of floating bodies.
 2. Centre of Pressure:

o The point on a submerged surface where the total pressure force can be considered
to act. It is used to calculate the torque about the axis of rotation.

3. Centre of Buoyancy:

o The center of the displaced volume of fluid by a floating object. It is the point where
the buoyant force acts and coincides with the centroid of the displaced volume.

4. Centre of Gravity:

o The point in a body where the entire weight of the body can be considered to act. It
is crucial for determining stability and balance.

5. Physical Quantity Unit Dimension

1. Force Newton (N) [MLT−2][M L T^{-2}][MLT−2]
2. Weight Newton (N) [MLT−2][M L T^{-2}][MLT−2]
3. Momentum kg·m/s [MLT−1][M L T^{-1}][MLT−1]
4. Impulse N·s [MLT−1][M L T^{-1}][MLT−1]
5. Work Joule (J) [ML2T−2][M L^2 T^{-2}][ML2T−2]
6. Energy Joule (J) [ML2T−2][M L^2 T^{-2}][ML2T−2]
7. Power Watt (W) [ML2T−3][M L^2 T^{-3}][ML2T−3]
8. Kinetic Energy Joule (J) [ML2T−2][M L^2 T^{-2}][ML2T−2]
9. Gravitational Potential Energy Joule (J) [ML2T−2][M L^2 T^{-2}][ML2T−2]
10. Torque Newton-meter (N·m) [ML2T−2][M L^2 T^{-2}][ML2T−2]
Here are 15 competitive exam MCQ questions related to casting, along with their answers:

1. Which of the following is a common material used for making molds in casting?

o A) Sand

o B) Concrete

o C) Plastic

o D) Wood
Answer: A) Sand

2. The process of pouring molten metal into a mold is known as:

o A) Forging

o B) Casting

o C) Welding

o D) Sintering
Answer: B) Casting

3. Which type of casting method is typically used for producing intricate parts like engine
blocks?
 o A) Die casting

o B) Investment casting

o C) Sand casting

o D) Centrifugal casting
Answer: B) Investment casting

4. What is the primary function of a gating system in casting?

o A) To control the flow of molten metal into the mold

o B) To cool down the mold

o C) To remove impurities from the metal

o D) To heat the metal before pouring

Answer: A) To control the flow of molten metal into the mold

5. Which of the following is a disadvantage of sand casting?

o A) High material cost

o B) Limited to small production runs

o C) Poor surface finish

o D) Inability to cast large parts

Answer: C) Poor surface finish

6. In which casting process is the mold made from a pattern coated with a thin layer of
ceramic material?

o A) Die casting

o B) Investment casting

o C) Shell molding

o D) Sand casting
Answer: B) Investment casting

7. Which of the following metals is commonly used in die casting?

o A) Aluminum

o B) Copper

o C) Iron

o D) Gold
Answer: A) Aluminum

8. Which factor affects the solidification time of a casting?

o A) Pouring temperature

o B) Mold material
 o C) Casting thickness

o D) All of the above

Answer: D) All of the above

9. What is the purpose of risers in the casting process?

o A) To allow the molten metal to enter the mold

o B) To provide a path for air to escape

o C) To supply extra metal to compensate for shrinkage

o D) To reinforce the mold

Answer: C) To supply extra metal to compensate for shrinkage

10. Which of the following is a common defect in casting?

o A) Cracks

o B) Porosity

o C) Cold shut

o D) All of the above

Answer: D) All of the above

11. What is the main advantage of using permanent molds in casting?

o A) Reduced cost per part in large production runs

o B) Ability to create complex shapes

o C) High flexibility for design changes

o D) Lower quality of the final product

Answer: A) Reduced cost per part in large production runs

12. What is the typical material used for investment casting molds?

o A) Sand

o B) Metal

o C) Ceramic

o D) Wood
Answer: C) Ceramic

13. Which casting process uses centrifugal force to distribute molten metal into a mold?

o A) Die casting

o B) Centrifugal casting

o C) Shell molding

o D) Sand casting
Answer: B) Centrifugal casting
14. What is a common disadvantage of die casting?

o A) High initial cost of mold

o B) Low production speed

o C) Difficulty in producing small parts

o D) Poor dimensional accuracy

Answer: A) High initial cost of mold

15. Which of the following is true for the investment casting process?

o A) It is used for producing high-volume parts.

o B) It allows for the casting of very intricate shapes.

o C) It is limited to non-ferrous metals only.

o D) It requires no additional finishing work.

Answer: B) It allows for the casting of very intricate shapes.

16. • Ideal Material: A hypothetical material that perfectly obeys Hooke's law under all
conditions of stress and strain.
17. • Uniform Material: A material with the same physical and mechanical properties
throughout its volume.
18. • Isotropic Material: A material with identical properties in all directions.
19. • Orthotropic Material: A material with different properties along three mutually
perpendicular axes