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: Centrifugal pumps are most efficient at which condition?
A) Minimum speed
B) Designed operating point
C) Shut-off head
D) Maximum flow rate
✅ Correct Answer: B
Explanation: Centrifugal pumps are designed for optimal performance at a specific flow and head known as the BEP (Best Efficiency Point).
Q: How does the Reynolds number influence flow characteristics?
A) Maintains uniform velocity
B) Determines laminar or turbulent
C) Increases pipe length
D) Controls pressure drop
✅ Correct Answer: B
Explanation: Reynolds number indicates whether the flow is laminar or turbulent.
Q: In gas welding, which flame is ideal for welding low carbon steel?
A) Cutting flame
B) Neutral flame
C) Oxidizing flame
D) Carburizing flame
✅ Correct Answer: B
Explanation: A neutral flame provides balanced combustion, suitable for most welding applications including low carbon steel.
Q: Why are heat exchangers used in power plants?
A) For combustion
B) For energy recovery
C) For vibration control
D) For noise reduction
✅ Correct Answer: B
Explanation: Heat exchangers recover heat from exhaust and improve overall thermal efficiency.
Q: Brinell hardness test uses which type of indenter?
A) Hardened steel ball
B) Diamond cone
C) Tungsten blade
D) Square punch
✅ Correct Answer: A
Explanation: Brinell test uses a hardened steel or tungsten carbide ball to indent the material.