Energy of the Electron & Energy Levels question from JEE Main 2023 (6 Apr, Shift 1)

Answer: (d)

1. Shortest wavelength means largest energy gap, since $\lambda = \frac{hc}{\Delta E}$.
2. $\Delta E \propto \frac{1}{n_f^2} - \frac{1}{n_i^2}$: A ($4\to3$) $= 0.049$, B ($4\to2$) $= 0.1875$, C ($3\to2$) $= 0.139$, D ($3\to1$) $= 0.889$.
3. D has the largest energy gap.
4. So the answer is (d) D.