78. The specific heat of air increases with increase in
A.Temperature
B.Pressure
C.Both pressure and temperature
D.Variation of its constituents

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79. Which of the following processes are thermodynamically reversible
A.Throttling
B.Free expansion
C.Isothermal and adiabatic
D.Hyperbolic and pV^n = C

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80. In order that a cycle be reversible, following must be satisfied
A.Free expansion or friction resisted expansion/compression process should not be encountered
B.When heat is being absorbed, temperature of hot source and working substance should be same
C.When beat is being rejected, temperature of cold source and working substance should be same
D.All of the above

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81. Which of the following processes is irreversible process
A.Isothermal
B.Adiabatic
C.Throttling
D.All of the above

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82. For a thermodynamic process to be reversible, the temperature difference between hot body and working substance should be
A.Zero
B.Minimum
C.maximum
D.Infinity

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83. Minimum work in compressor is possible when the value of adiabatic index n is equal to
A.0.75
B.1
C.1.27
D.1.35

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84. A gas is compressed in a cylinder by a movable piston to a volume one-half its original volume during the process 300 kJ heat left the gas and internal energy remained sameThe work done on gas in Nm will be
A.300 Nm
B.300,000 Nm
C.30 Nm
D.3,000 Nm

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