Easy MCQ +4 / -1 PYQ · JEE Mains 2025

Match the List I with List II

List - I List - II
(A) Triatomic rigid gas (I) $\frac{C_p}{C_v}=\frac{5}{3}$
(B) Diatomic non-rigid gas (II) $\frac{C_p}{C_v}=\frac{7}{5}$
(C) Monoatomic gas (III) $\frac{C_p}{C_v}=\frac{4}{3}$
(D) Diatomic rigid gas (IV) $\frac{C_p}{C_v}=\frac{9}{7}$

Choose the correct answer from the options given below:

  1. A A-III, B-IV, C-I, D-II Correct answer
  2. B A-II, B-IV, C-I, D-III
  3. C A-IV, B-II, C-III, D-I
  4. D A-III, B-II, C-IV, D-I

Solution

<p>The explanation uses the equation for the heat capacity ratio, $ \gamma = 1 + \frac{2}{\text{f}} $, where $ \text{f} $ is the degrees of freedom of the gas. Here's how it applies to different types of gases:</p> <p><strong>Triatomic Rigid Gas</strong>: </p> <p><p>Degrees of freedom ($ \text{f} $) = 6</p></p> <p><p>$ \gamma = 1 + \frac{2}{6} = \frac{4}{3} $</p></p> <p><strong>Diatomic Non-Rigid Gas</strong>: </p> <p><p>Degrees of freedom ($ \text{f} $) = 7</p></p> <p><p>$ \gamma = 1 + \frac{2}{7} = \frac{9}{7} $</p></p> <p><strong>Diatomic Rigid Gas</strong>: </p> <p><p>Degrees of freedom ($ \text{f} $) = 5</p></p> <p><p>$ \gamma = 1 + \frac{2}{5} = \frac{7}{5} $</p></p> <p><strong>Monoatomic Gas</strong>: </p> <p><p>Degrees of freedom ($ \text{f} $) = 3</p></p> <p><p>$ \gamma = 1 + \frac{2}{3} = \frac{5}{3} $</p></p> <p>Therefore, when matching List I with List II, the correct pairing is:</p> <p><p><strong>A</strong> (Triatomic rigid gas) - <strong>III</strong> $(\frac{4}{3})$</p></p> <p><p><strong>B</strong> (Diatomic non-rigid gas) - <strong>IV</strong> $(\frac{9}{7})$</p></p> <p><p><strong>C</strong> (Monoatomic gas) - <strong>I</strong> $(\frac{5}{3})$</p></p> <p><p><strong>D</strong> (Diatomic rigid gas) - <strong>II</strong> $(\frac{7}{5})$</p></p> <p>Thus, the correct answer from the options given is:</p> <p><strong>A-III, B-IV, C-I, D-II</strong></p>

About this question

Subject: Physics · Chapter: Thermodynamics · Topic: Thermodynamic Processes

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