Degrees of freedom — UPSC Physics Optional CSE 1997 Paper I

A gas at a pressure P and temperature T has a density \rho. The velocity of sound in this gas is v. Obtain an expression for the degrees of freedom of the gas molecules. At STP, \rho = 1.3\text{ kg m}^{-3} and \text{v} = 330\text{ ms}^{-1}. Calculate the degrees of freedom.