Practice portal › Kinetic Theory of Gases › Degrees of Freedom and Equipartition

γ_A is the specific heat ratio of a monoatomic gas A having 3 translational degrees of freedom. γ_B is the specific heat ratio of a polyatomic gas B having 3 translational, 3 rotational degrees of freedom and 1 vibrational mode. If (γ_A)/(γ_B) = (1 + 1/n), then the value of n is ______.

Asked in JEE Main 2nd April 1st Shift 2025 · Vibrational modes

Answer: 3

Step-by-step solution

Gas A is monoatomic: f_A=3, so γ_A=1+2/3=5/3.

Gas B has 3 translational and 3 rotational modes plus one vibration, which counts twice.

f_B=3+3+2=8, so γ_B=1+2/8=5/4.

(γ_A)/(γ_B)=(5/3)/(5/4)=4/3=1+1/3.

So n=3.

More Degrees of Freedom and Equipartition questionsAll Degrees of Freedom and Equipartition questions →

Reading this solution needs no sign-in. You only sign in to practise against the clock and keep your progress.

Practise this with a timer