Easy MCQ +4 / -1 PYQ · JEE Mains 2023

A hypothetical gas expands adiabatically such that its volume changes from 08 litres to 27 litres. If the ratio of final pressure of the gas to initial pressure of the gas is $\frac{16}{81}$. Then the ratio of $\frac{\mathrm{Cp}}{\mathrm{Cv}}$ will be.

  1. A $\frac{3}{1}$
  2. B $\frac{4}{3}$ Correct answer
  3. C $\frac{1}{2}$
  4. D $\frac{3}{2}$

Solution

Let $\gamma$ be the ratio of $\frac{C_{p}}{C_{v}}$ <br/><br/>Then for adiabatic process <br/><br/>$$ \begin{aligned} & P V^{\gamma}=\text { Constant } \\\\ & \Rightarrow \frac{P_{i}}{P_{f}}=\left(\frac{V_{f}}{V_{i}}\right)^{\gamma} \\\\ & \Rightarrow \frac{81}{16}=\left(\frac{27}{8}\right)^{\gamma} \\\\ & \Rightarrow \gamma=\frac{4}{3} \end{aligned} $$

About this question

Subject: Physics · Chapter: Thermodynamics · Topic: Zeroth and First Law

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