JEE Main 2025 Apr 2 Shift 2, Physics Q22: Law of Equipartition of Energy

For a diatomic ideal gas the internal energy is $U=n{C}_{v}T=n\cdot \frac{5R}{2}\cdot T$. Using $PV=nRT$:

$U=\frac{5}{2}PV$.

With $P=10^5$ Pa and $V=4\times 4\times 3=48{\text{m}}^3$:

$U=\frac{5}{2}\times 10^5\times 48=1.2\times 10^7\text{J}=12\times 10^6\text{J}$.

$\therefore$ the numerical coefficient is $12$.