83) For a thermodynamic process to be reversible, the temperature difference between hot body and working substance should be

84) Minimum work in compressor is possible when the value of adiabatic index n is equal to

85) Molecular volume of any perfect gas at 600 x 103 N/m2 and 27°C will be

86) 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 same. The work done on gas in Nm will be

87) The more effective way of increasing efficiency of Carnot engine is to