How many rotational degrees of freedom does a rigid diatomic molecule have?

What will be the average value of energy for a monoatomic gas in thermal equilibrium at temperature $T$?

Define degree of freedom.

If the internal energy of $3$ moles of a gas at a temperature of $27^{\circ} C$ is $2250 R$,then the number of degrees of freedom of the gas is (where $R$ is the universal gas constant).

At standard temperature and pressure $(STP)$,the density of a gas is $1.3 \ kg/m^3$ and the speed of sound in the gas is $330 \ m/s$. The degree of freedom of the gas is:

$A$ diatomic gas consisting of rigid molecules is at a temperature of $87^{\circ} C$. If the moment of inertia of the rotating diatomic rigid molecule is $2.76 \times 10^{-39} \text{ g cm}^2$,then the rms angular speed of the molecule is (Boltzmann constant $= 1.38 \times 10^{-23} \text{ J K}^{-1}$).