JEE Main 2026 — 24 January, Morning Shift — Question 27

$\mathrm{Q}=\mathrm{mS} \Delta \mathrm{T}=4 \times 4200 \times 16 \mathrm{~J}=268800 \mathrm{~J}$ $\mathrm{W}=\mathrm{P} \Delta \mathrm{V}$ $\Delta \mathrm{V}=\left(\frac{\mathrm{m}}{\rho_{\mathrm{f}}}-\frac{\mathrm{m}}{\rho_{\mathrm{i}}}\right)=4\left[\frac{1}{998}-\frac{1}{1000}\right]$ $\mathrm{P}=10^{5} \mathrm{~Pa}$. $\therefore \mathrm{W}=10^{5} \times 4 \times\left[\frac{1}{998}-\frac{1}{1000}\right]=\frac{8 \times 10^{5}}{10^{3} \times 998} \approx 0.8 \mathrm{~J}$ $\Delta \mathrm{U}=\mathrm{Q}-\mathrm{W}=268799.2 \mathrm{~J}$