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: Internal energy of a system increases when heat is added at constant volume
A) No temperature change
B) All the above
C) Work done by system
D) No heat transfer
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Correct Answer: D
Explanation: At constant volume, no work is done, so heat increases internal energy.
Q: Steam turbines are preferred over gas turbines for
A) High initial cost
B) Constant load conditions
C) Low pressure application
D) Quick start-up
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Correct Answer: B
Explanation: Steam turbines are ideal for steady, base-load conditions due to efficiency.
Q: The ratio of specific heats (ฮณ = Cp/Cv) for air is nearly
A) 1.0
B) 1.4
C) 1.33
D) 1.67
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Correct Answer: B
Explanation: For diatomic gases like air, ฮณ is typically 1.4.
Q: Rankine cycle efficiency increases when
A) Boiler pressure is reduced
B) Condenser pressure is increased
C) Superheating is done
D) Feedwater is cooled
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Correct Answer: C
Explanation: Superheating improves thermal efficiency by reducing moisture in turbine exhaust.
Q: Hardness of a material is its ability to
A) Resist deformation
B) Resist wear and abrasion
C) Break easily
D) Withstand impact
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Correct Answer: B
Explanation: Hardness measures a material's resistance to surface indentation and abrasion.