Q 11-12-019NEETJEE MainMedium
A diatomic gas is at a high enough temperature that its vibrational mode is also excited. Its ratio of specific heats $\gamma$ is
Answer: (A) $\dfrac{9}{7}$
Concept. $\gamma = 1 + \dfrac{2}{f}$; vibration adds 2 degrees of freedom.
Step 1. Degrees of freedom. $3 + 2 + 2 = 7$.
Step 2. $\gamma$. $1 + \dfrac27 = \dfrac97$.
Answer. $\dfrac97$ (Option A).
Solution by Sreeraj P, M.Sc Physics