4.0 g of a gas occupies 22.4 L at NTP. The specific heat capacity of the gas at constant volume is 5.0 JK^-1 mol^-1. If the speed of sound in this gas at NTP is 952 ms^-1, then the heat capacity at constant pressure is.
(Take gas constant R = 8.3 Jk^-1 mol^-1)

• 8.0 JK^-1mol^-1

• 7.5 JK^-1mol^-1

• 7.0 JK^-1mol^-1

• 8.5 JK^-1mol^-1

A Carnot engine whose sink is at 300 K has an efficiency of 40%. By how much should the temperature of source be increased so as to increase its efficiency by 50% of original efficiency?

• 275 K

• 175 K

• 250 K

• 225 K

A Carnot engine, having an efficiency of as heat engine, is used as a refrigerator. If the work is done on the system is 10J, the amount of energy absorbed from the reservoir at lower temperature is

• 100J 

• 99 J 

• 90 J

• 1 J 

A gas is compressed isothermally to half its initial volume. The same gas is compressed separately through an adiabatic process until its volume is again reduced its half. Then,

• compressing the gas through adiabatic process will require more work to b done

• compressing the gas through isothermally or adiabatically will require the same amount of work.

• which of the case (whether compression through isohermal or through adiabatic process) requires more work will depend upon the atomicity of the gas.

• compressing the gas isothermally will require more work to be done

B.

compressing the gas through isothermally or adiabatically will require the same amount of work.

Plotting P-V graph for the compression of a gas isothermally and adiabatically simultaneously to half of its initial volume.

An isothermal curve is less steeper than the adiabatic curve. So, area under the P-V curve for adiabatic process has more magnitude than the isothermal curve. Hence, work done in adiabatic process will be more than in isothermal process.

A gas is taken through the cycle A → B → C → A, as shown, What is the net work done by the gas?

• 2000 J

• 1000 J

• Zero

• -2000 J