A polyatomic gas $(\gamma=4 / 3)$ is compressed to $\left(\frac{1}{8}\right)^{\text {th }}$ of its volume…

A polyatomic gas $(\gamma=4 / 3)$ is compressed to $\left(\frac{1}{8}\right)^{\text {th }}$ of its volume adiabatically.If its initial pressure is $\mathrm{P}_0$, its new pressure will be
  1. $2 \mathrm{P}_0$
  2. $8 \mathrm{P}_0$
  3. $6 \mathrm{P}_0$
  4. $16 \mathrm{P}_0$

Solution

For adiabatic expression, we have $\begin{aligned} & \mathrm{P}_2 \mathrm{~V}_2^\gamma=\mathrm{P}_1 \mathrm{~V}_1^\gamma \\ & \therefore \frac{\mathrm{P}_2}{\mathrm{P}_1}=\left(\frac{\mathrm{V}_1}{\mathrm{~V}_2}\right)^\gamma=(8)^{\frac{4}{3}}=16 \\ & \therefore \mathrm{P}_2=16 \mathrm{P}_1=16 \mathrm{P}_0 \end{aligned}$ *

Asked in: MHT CET 2021 (22 Sep Shift 1)

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