Consider two ideal diatomic gases A and B at some temperature $T$. Molecules of the gas $A$ are rigid, and have a mass m . Molecules of the gas $B$ have an additional vibrational mode, and have a mass $\frac{m}{4}$.The ratio of the specific heats $\left(C_v^B\right.$ and $\left.C_v^B\right)$ of gas $A$ and $B$, respectively is:
