JEE Main 2026 — 21 January, Morning Shift — Question 26

Water flow rate $=5 \ell / \min =\frac{5}{60} \mathrm{~kg} / \mathrm{s}$ ∴ Power of heater $=\frac{\mathrm{dm}}{\mathrm{dt}} \mathrm{S} \Delta \mathrm{T}=\frac{1}{12} \times 4200 \times 60 \mathrm{~W}$ ∴ Let rate of consumption of gas be $\mathrm{x} \mathrm{g} / \mathrm{s}$. $\therefore \quad \mathrm{x} \times 5.0 \times 10^{4}=\frac{1}{12} \times 4200 \times 60$ $\Rightarrow \quad \mathrm{x}=4200 \times 10^{-4}=0.42 \mathrm{~g} / \mathrm{s}$ Correct option (3)