Mechanical Engineering MCQs
Mechanical Engineering MCQs are a crucial resource for students and job seekers preparing for competitive tests in Pakistan. This section features MCQs from all major areas including thermodynamics, fluid mechanics, machine design, manufacturing processes, engineering materials, and mechanics of solids. These questions are crafted to meet the standards of exams like PPSC, FPSC, NTS, and university entry or semester tests. Each MCQ is aimed at testing your fundamental understanding and problem-solving ability, making them perfect for both fresh graduates and experienced professionals. With a wide range of topics, this category ensures a comprehensive practice session for anyone looking to ace Mechanical Engineering exams.
Q: Poisson’s ratio is defined as the ratio of
A) Lateral strain to axial strain
B) Stress to strain
C) Axial strain to lateral strain
D) Shear strain to shear stress
✅ Correct Answer: A
Explanation: Poisson’s ratio is lateral strain divided by axial strain.
Q: Heat is transferred by conduction when
A) Bodies are at same temperature
B) Molecular interaction occurs
C) Radiation dominates
D) There’s motion of fluid
✅ Correct Answer: B
Explanation: Conduction involves transfer through molecular contact.
Q: Unit of thermal conductivity in SI is
A) W/K
B) W/m·K
C) W/m
D) W/m²
✅ Correct Answer: B
Explanation: Thermal conductivity is measured in watts per meter-Kelvin.
Q: In gas turbines, intercooling is used to
A) Reduce work input
B) Increase temperature
C) Increase combustion
D) Increase pressure
✅ Correct Answer: A
Explanation: Intercooling cools compressed air before the next compression stage, reducing work input.
Q: The term “degree of freedom” in mechanics refers to
A) Types of motion
B) Modes of vibration
C) Number of independent motions
D) Number of constraints
✅ Correct Answer: C
Explanation: It refers to the minimum number of independent coordinates needed to define motion.
Q: Mohr’s circle is used to determine
A) Shear and normal stresses
B) Torque
C) Stress concentration
D) Moments
✅ Correct Answer: A
Explanation: Mohr’s circle graphically represents stress transformations.
Q: Euler’s formula is used to calculate
A) Stress
B) Buckling load
C) Bending moment
D) Heat loss
✅ Correct Answer: B
Explanation: Euler's formula gives critical buckling load for long slender columns.
Q: Welding process involving non-consumable electrode is
A) Resistance welding
B) MIG
C) TIG
D) Arc welding
✅ Correct Answer: C
Explanation: TIG uses a non-consumable tungsten electrode for welding.
Q: In reciprocating compressors, clearance volume is necessary to
A) Prevent fluid leakage
B) Avoid piston striking
C) Reduce friction
D) Avoid knocking
✅ Correct Answer: B
Explanation: Clearance prevents mechanical contact between piston and cylinder head.
Q: The main function of lubricating oil is to
A) Increase temperature
B) Clean components
C) Decrease power
D) Reduce wear
✅ Correct Answer: D
Explanation: Lubrication reduces friction and wear between moving parts.