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: When a beam is subjected to pure bending
A) Deflection is zero
B) No stress develops
C) Only normal stress exists
D) Shear stress occurs
✅ Correct Answer: C
Explanation: Pure bending causes only normal stresses in cross section.
Q: Factor of safety is defined as
A) Breaking load / Design load
B) Yield stress / Allowable stress
C) Maximum load / Working load
D) Ultimate stress / Allowable stress
✅ Correct Answer: D
Explanation: It provides a margin between expected and failure loads.
Q: Gear ratio is determined by
A) Gear size
B) Torque
C) Pitch circle diameter
D) Number of teeth
✅ Correct Answer: D
Explanation: Gear ratio is calculated by dividing teeth of driven gear by driving gear.
Q: Specific speed of a pump is used to classify
A) Cavitation
B) Impellers
C) Turbines
D) Flow types
✅ Correct Answer: B
Explanation: Specific speed helps select the most efficient pump design.
Q: Diesel engines use
A) Battery ignition
B) Carburetor
C) Spark plug
D) Fuel injection
✅ Correct Answer: D
Explanation: Diesel engines use compression ignition with direct fuel injection.