For a gas, $\frac{\mathrm{R}}{\mathrm{C}_{\mathrm{V}}}=0.4$, where $\mathrm{R}$ is universal gas constant…
For a gas, $\frac{\mathrm{R}}{\mathrm{C}_{\mathrm{V}}}=0.4$, where $\mathrm{R}$ is universal gas constant and $\mathrm{C}_{\mathrm{v}}$ is molar specific heat at constant volume. The gas is made up of molecules which are
rigid diatomic
monoatomic
non-rigid diatomic
polyatomic
Solution
Given: $\frac{\mathrm{R}}{\mathrm{C}_{\mathrm{v}}}=0.4$
$\begin{aligned}
\mathrm{C}_{\mathrm{V}} & =\frac{\mathrm{R}}{0.4}=\frac{5 \mathrm{R}}{2} \\
\mathrm{C}_{\mathrm{P}} & =\mathrm{C}_{\mathrm{V}}+\mathrm{R} \\
\therefore \quad \mathrm{C}_{\mathrm{P}} & =\frac{7 \mathrm{R}}{2} \\
\gamma & =\frac{\mathrm{C}_{\mathrm{P}}}{\mathrm{C}_{\mathrm{V}}}=\frac{\frac{7}{2}}{\frac{5}{2}} \\
\gamma & =\frac{7}{5}
\end{aligned}$
$\therefore \quad$ The gas is made up of rigid diatomic molecules.