Q 11-12-024NEETJEE MainEasy
The internal energy of one mole of a rigid diatomic ideal gas at temperature $T$ is
Answer: (B) $\dfrac{5}{2}RT$
Concept. Equipartition: $\dfrac12RT$ per mole per degree of freedom.
Step 1. Rigid diatomic. 3 translational $+$ 2 rotational $= 5$: $U = \dfrac52RT$.
Answer. $\dfrac52RT$ (Option B).
Solution by Sreeraj P, M.Sc Physics