Question

$\gamma$ is the ratio of molar specific heat capacity of the given gas at ......................... to its specific heat capacity at ........................... .

• A. Constant temperature, Constant volume
• B. Constant volume, Constant pressure
• C. Constant pressure, Constant temperature
• D. Constant pressure, Constant volume

Answer 1

Answer: (D)

Constant pressure, Constant volume

Two specific heats are defined for gases, one for constant volume ($C_v)$) and one for constant pressure ($C_p)$).

$\gamma$ is the ratio of molar specific heat capacity of the given gas at constant pressure to its specific heat capacity at constant volume ($C_p/C_v$).
The ratio of the specific heats $\gamma =C_p/C_v$ is a factor in adiabatic engine processes and in determining the speed of sound in a gas.

This ratio $\gamma =1.66$ for an ideal monoatomic gas and $\gamma =1.4$ for air, which is predominantly a diatomic gas.