AIIMS 2019 Physics Specific Heat Capacities MCQ Question

In the context of specific heat capacities for ideal gases, the ratio $\frac{C_v}{C_p}$ is derived from the degrees of freedom of the gas molecules. For a diatomic gas, which has 5 degrees of freedom, the specific heat capacities are $C_v = \frac{5R}{2}$ and $C_p = \frac{7R}{2}$, leading to $\frac{C_v}{C_p} = \frac{5}{7}$. This indicates that option B is correct for diatomic gases. However, the question specifically asks for the ratio of $C_v$ to $C_p$ for a monoatomic gas, which is $\frac{3}{5}$, corresponding to option A. Therefore, option C (7/5) is incorrect as it does not represent the ratio for either gas type.