Thermodynamics MCQ Questions Answers Mechanical Engineering

11) Work done is zero for the following process

a) constant volume

b) free expansion

c) throttling

d) all of the above

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Option – d)

12) In free expansion process

a) W1-2 =0

b) Q1-2 = 0

c) du = 0

d) All of the above

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Option – d)

13) Internal energy is defined by

a) Zeroth law of thermodynamics

b) first law of thermodynamics

c) Second law of thermodynamics
d) Law of entropy

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Option – b)

14) The first law of thermodynamics is the law of

a) conservation of mass

b) conservation of energy

c) conservation of momentum

d) conservation of temperature

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Option – b)

15) Compressed air coming out from a punctured football

a) becomes hotter

b) becomes cooler

c) remains at same temperature

d) attains atmospheric temperature

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Option – b)

16)Second law of thermodynamics defines

a) Heat

b) Work

c) Enthalpy

d) Entropy

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Option – d)

17) Kelvin-plank law deals with

a) conservation of energy

b) conservation of heat

c) conservation of mass

d) conservation of heat into work

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Option – d)

18) If a heat engine gives an output of 3 kW when the input is 10000J/sec then the thermal efficiency of the engine will be

a) 20%

b) 30%

c) 70%

d) 76.7%

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Option – b)

19) When a system is in equilibrium, any conceivable change in entropy would be

a) maximum

b) zero

c) positive

d) negative

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Option – b)

20) The value of entropy at 0k is taken as

a) 1

b) 0

c) -1

d) any value

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Option – a)