Q 11-11-067JEE MainJEE Main 2024 (27 Jan, Shift 1)Easy
$0.08\ \text{kg}$ air is heated at constant volume through $5\,^\circ\text{C}$. The specific heat of air at constant volume is $0.17\ \text{kcal kg}^{-1}\,^\circ\text{C}^{-1}$ and $J = 4.18\ \text{joule cal}^{-1}$. The change in its internal energy is approximately:
Answer: (C) $284\ \text{J}$
At constant volume no work is done, so all the heat supplied goes into internal energy:
$$\Delta U = m c_v \Delta T = 0.08\times0.17\times5 = 0.068\ \text{kcal} = 68\ \text{cal}$$
$$\Delta U = 68\times4.18 \approx 284\ \text{J}$$
Solution by Sreeraj P, M.Sc Physics