The ratio of specific heat at constant pressure to specific heat at constant volume $(\gamma)$ for a gas is…
The ratio of specific heat at constant pressure to specific heat at constant volume $(\gamma)$ for a gas is $\left(1+\frac{2}{\mathrm{f}}\right)$ where $\mathrm{f}$ is the number of degrees of freedom of a molecule of a gas. The ratio of ' $\gamma_{d}$ ' for rigid diatomic to ' $\gamma_{\mathrm{m}}$ ' for monoatomic is
$\frac{14}{23}$
$\frac{25}{21}$
$\frac{21}{25}$
$\frac{23}{14}$
Solution
For monoatomic gas
\(Y_1=\frac{5}{3}\)
For diatomic gas at low temperatures
\(\begin{aligned}
& Y_2=\frac{7}{5} \\
& \therefore \frac{\gamma_1}{\gamma_2}=\frac{\frac{5}{3}}{\frac{7}{5}}=\frac{25}{21}
\end{aligned}\)
add this part at last
\(\frac{\gamma_2}{\gamma_1}=\frac{21}{25}\)