The molar specific heats of an ideal gas at constant pressure and volume are denoted by C_P and  C_V respectively.  If  $\mathrm{\gamma } = \frac{{\mathrm{C}}_{\mathrm{P}}}{{\mathrm{C}}_{\mathrm{V}}}$ and R is then C_V universal gas constant, then C_V is equal to

• $\frac{\mathrm{\gamma } - 1}{\mathrm{R}}$

• γR

• $\frac{1 + \mathrm{\gamma }}{1 - \mathrm{\gamma }}$

• $\frac{\mathrm{R}}{\left(\mathrm{\gamma } - 1\right)}$

Conversion of water to steam is accompanied by which process?

• Adiabatic

• Isothermal

• Isochoric

• Cyclic

An ideal gas is taken through the cycle A → B → C → A, as shown in figure. If the net heat supplied to the gas in the cycle is  5 J  the work done by the gas in the process A → B is

• 2 J

• 3 J

• 4 J

• 5 J

What is the slope for an isothermal process?

• $\frac{\mathrm{P}}{\mathrm{V}}$

• $- \frac{\mathrm{P}}{\mathrm{V}}$

• Zero

• ∞

For an adiabatic process

• ΔS = 0

• Δu = 0

• Q = 0

• W = 0

For cyclic process which of the following quantity is zero? 

• ΔV

• Δu

• W

• ΔQ

Assertion:  During rapid pumping of air in tyres, air inside the tyre is hotter than atmospheric air.

Reason:  Adiabatic process occurs at very high rate.

• If both assertion and reason are true and reason is correct explanation of assertion.

• If both assertion and reason are true but reason is not correct explanation of assertion. 

• If assertion is true but reason is false.

• If both assertion and reason are false.

228.

The latent heat of vaporisation of a substance is always

• greater than its latent heat of fusion

• greater than its latent heat of sublimation

• equal to its latent heat of sublimation

• less than its latent heat of fusion

A reversible engine converts one-sixth of the heat input into work. When the temperature of the sink is reduced by   62°C, the efficiency of the engine is doubled. The temperatures of the source and sink are

• 99^oC, 37^oC

• 80^oC, 37^oC

• 95^oC, 37^oC

• 90^oC, 37^oC

Graph of specific heat at constant volume for a monoatomic gas is