JEE Main 2025 — Thermodynamics Question with Solution
JEE Main 2025 (22 Jan Shift 2)
Question
For a diatomic gas, if for rigid molecules and for another diatomic molecules, but also having vibrational modes. Then, which one of the following options is correct ? (Cp and Cv are specific heats of the gas at constant pressure and volume)
Choose an option
Show full solutionCorrect option: C
Correct answer
C
Step-by-step explanation
For rigid diatomic molecules
$\begin{array}{ll}
& f=5 \\
\therefore & \gamma_1=\frac{7}{5}=1.4
\end{array}$
For non-rigid diatomic molecules
$\begin{array}{ll}
& f=5+2=7 \\
& \gamma_2=\frac{9}{7}=1.28 \\
\therefore & \gamma_1>\gamma_2
\end{array}$
Practice this on the real CBT interface
Solve this JEE Main question (and the rest of the Thermodynamics chapter) on PrepSharp's TCS iON-style CBT player — with timer, bookmarks and session analytics.
Solve interactively →About this question
This is a previous-year question from JEE Main 2025, covering the Thermodynamics chapter of Physics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.