Mechanical Engineer Intern Certification
Exam Practice Questions And Correct
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Rationale 2026 Q&A| Instant Download
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1. A shaft is subjected to a torque of 500 N·m. If its polar moment of
inertia is doubled while keeping all other factors constant, what
happens to the maximum shear stress?
A. It doubles
B. It remains unchanged
C. It is halved
D. It becomes zero
Answer: C
The torsional shear stress in a circular shaft is inversely proportional
to the polar moment of inertia, so doubling the polar moment of
inertia reduces the maximum shear stress by half.
2. Which of the following materials has the highest thermal conductivity?
A. Rubber
B. Glass
C. Copper
D. Wood
, Answer: C
Copper has a very high thermal conductivity compared to non-
metallic materials due to its free electron structure, making it highly
efficient at heat transfer.
3. The efficiency of a Carnot engine depends on which of the following?
A. Working fluid
B. Pressure ratio only
C. Temperature limits only
D. Volume of the system
Answer: C
Carnot efficiency depends solely on the temperatures of the heat
source and sink, not on the working fluid or other system properties.
4. What is the unit of dynamic viscosity in SI units?
A. Pa·s
B. N/m²
C. kg/m³
D. m²/s
Answer: A
Dynamic viscosity is measured in Pascal-seconds, which is equivalent
to N·s/m², representing resistance to fluid flow.
5. Which law governs the relationship between stress and strain in the
elastic region?
A. Newton’s law
B. Hooke’s law
C. Boyle’s law
D. Charles’s law
Answer: B
Hooke’s law states that within elastic limits, stress is directly
proportional to strain.
, 6. In a simply supported beam with a central point load, the maximum
bending moment occurs at:
A. Supports
B. Quarter span
C. Midspan
D. Free end
Answer: C
For a central point load, the maximum bending moment occurs at the
midpoint of the beam due to symmetry.
7. Which process increases the hardness of steel by rapid cooling?
A. Annealing
B. Normalizing
C. Quenching
D. Tempering
Answer: C
Quenching rapidly cools steel, trapping carbon in solution and
increasing hardness.
8. The second law of thermodynamics introduces the concept of:
A. Energy conservation
B. Entropy
C. Momentum
D. Enthalpy
Answer: B
The second law introduces entropy, indicating the directionality and
irreversibility of natural processes.
9. What is the primary function of a flywheel?
A. Increase torque output
B. Store kinetic energy
C. Reduce friction
Exam Practice Questions And Correct
Answers (Verified Answers) Plus
Rationale 2026 Q&A| Instant Download
1. A shaft is subjected to a torque of 500 N·m. If its polar moment of
inertia is doubled while keeping all other factors constant, what
happens to the maximum shear stress?
A. It doubles
B. It remains unchanged
C. It is halved
D. It becomes zero
Answer: C
The torsional shear stress in a circular shaft is inversely proportional
to the polar moment of inertia, so doubling the polar moment of
inertia reduces the maximum shear stress by half.
2. Which of the following materials has the highest thermal conductivity?
A. Rubber
B. Glass
C. Copper
D. Wood
, Answer: C
Copper has a very high thermal conductivity compared to non-
metallic materials due to its free electron structure, making it highly
efficient at heat transfer.
3. The efficiency of a Carnot engine depends on which of the following?
A. Working fluid
B. Pressure ratio only
C. Temperature limits only
D. Volume of the system
Answer: C
Carnot efficiency depends solely on the temperatures of the heat
source and sink, not on the working fluid or other system properties.
4. What is the unit of dynamic viscosity in SI units?
A. Pa·s
B. N/m²
C. kg/m³
D. m²/s
Answer: A
Dynamic viscosity is measured in Pascal-seconds, which is equivalent
to N·s/m², representing resistance to fluid flow.
5. Which law governs the relationship between stress and strain in the
elastic region?
A. Newton’s law
B. Hooke’s law
C. Boyle’s law
D. Charles’s law
Answer: B
Hooke’s law states that within elastic limits, stress is directly
proportional to strain.
, 6. In a simply supported beam with a central point load, the maximum
bending moment occurs at:
A. Supports
B. Quarter span
C. Midspan
D. Free end
Answer: C
For a central point load, the maximum bending moment occurs at the
midpoint of the beam due to symmetry.
7. Which process increases the hardness of steel by rapid cooling?
A. Annealing
B. Normalizing
C. Quenching
D. Tempering
Answer: C
Quenching rapidly cools steel, trapping carbon in solution and
increasing hardness.
8. The second law of thermodynamics introduces the concept of:
A. Energy conservation
B. Entropy
C. Momentum
D. Enthalpy
Answer: B
The second law introduces entropy, indicating the directionality and
irreversibility of natural processes.
9. What is the primary function of a flywheel?
A. Increase torque output
B. Store kinetic energy
C. Reduce friction
