JEE Main 2026 — 28 January, Evening Shift — Question 34

$\mathrm{V}_{\text {sound }}=\sqrt{\frac{\mathrm{Y}}{\rho}}$ $\frac{\Delta \mathrm{V}}{\mathrm{V}} \times 100=\frac{1}{2}\left(\frac{\Delta \mathrm{Y}}{\mathrm{Y}} \times 100\right)-\frac{1}{2}\left(\frac{\Delta \rho}{\rho} \times 100\right)$ $=\frac{1}{2} \times 1-\frac{1}{2} \times 0.5$ $\frac{\Delta \mathrm{V}}{\mathrm{V}} \times 100=\frac{1}{4}$ $\Delta \mathrm{V}=\frac{1}{4} \times \frac{\mathrm{V}}{100}$ $\Delta \mathrm{V}=1 \mathrm{~m} / \mathrm{s}$ $V_{\text {final }}=400+1=401 \mathrm{~m} / \mathrm{s}$