Mechanical Engineering MCQs
Mechanical Engineering MCQs for competitive exams in Pakistan cover thermodynamics, fluid mechanics, machine design, manufacturing, and materials. Ideal for PPSC, FPSC, NTS, and university tests, they help students and professionals enhance concepts and problem-solving skills.
Q: Gear ratio determines what in a gear mechanism?
A) Mass flow rate
B) Fuel consumption
C) Surface roughness
D) Torque and speed
✅ Correct Answer: D
Explanation: Gear ratio is used to calculate output torque and rotational speed.
Q: Which type of turbine is ideal for high head and low flow conditions?
A) Pelton wheel
B) Francis
C) Reaction
D) Kaplan
✅ Correct Answer: A
Explanation: Pelton turbines are best suited for high head applications with small flow rates.
Q: Is fatigue failure more likely under which type of loading?
A) Uniform thermal
B) Repeated cyclic
C) Steady magnetic
D) Constant static
✅ Correct Answer: B
Explanation: Fatigue failure typically occurs due to repeated cyclic stress, even below yield strength.
Q: The Prandtl number relates which two physical phenomena?
A) Work and time
B) Strain and stress
C) Momentum and heat transfer
D) Pressure and volume
✅ Correct Answer: C
Explanation: It is a dimensionless number comparing momentum diffusivity and thermal diffusivity.
Q: Why is lubrication essential in bearings?
A) To block vibration
B) To increase heat
C) To reduce friction
D) To slow rotation
✅ Correct Answer: C
Explanation: Lubrication reduces friction and prevents wear and overheating in bearings.