MCQ Collection
Pakistan MCQs
Practice Pakistan questions with answers and explanations.
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Correct Answer: A. 1,002,000 J
Explanation:
Use Q=mL.
Q=3×334,000 = 1,002,000 J.
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Correct Answer: B. 2 × 10^-5 °C^-1
Explanation:
Use α=ΔL/(LΔT).
α=0.002/(2×50)=2×10^-5 °C^-1.
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Correct Answer: C. 200 kPa
Explanation:
Boyle's law gives P1V1=P2V2.
P2=100×4/2 = 200 kPa.
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Correct Answer: D. 4 L
Explanation:
Charles's law gives V/T constant.
V2=3×400/300 = 4 L.
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Correct Answer: A. 4986 J
Explanation:
The ideal-gas equation gives PV=nRT.
PV=2×8.31×300 = 4986 J.
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Correct Answer: B. 300 J
Explanation:
Using ΔU=Q-W for work done by the gas.
ΔU=500-200 = 300 J.
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Correct Answer: C. -300 J
Explanation:
Take Q=-400 J and work done by the gas W=-100 J.
ΔU=Q-W=-400-(-100)=-300 J.
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Correct Answer: D. 30%
Explanation:
Efficiency is work output divided by heat input.
300/1000×100 = 30%.
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Correct Answer: A. 6 m/s
Explanation:
Continuity gives A₁v₁=A₂v₂.
V₂=0.06×2/0.02 = 6 m/s.
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Correct Answer: A. Pressure is inversely proportional to volume
Explanation:
For an isothermal ideal-gas process, PV is constant.
Reducing volume raises pressure.
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Correct Answer: B. 0.002
Explanation:
Strain is extension divided by original length.
0.004/2 = 0.002.
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Correct Answer: B. Volume is proportional to absolute temperature
Explanation:
At fixed pressure, heating an ideal gas increases its volume.
Temperature must be measured on an absolute scale.
