Hydrogen Spectrum & Spectral Series question from JEE Main 2026 (22 Jan, Shift 2)

Answer: (c)

1. Lyman smallest: $\frac{1}{R} = 91$ nm
2. Paschen largest ($4 \to 3$): $\lambda_P = \frac{144}{7R} = \frac{144}{7}\times 91 = 1872$ nm
3. Balmer largest ($3 \to 2$): $\lambda_B = \frac{36}{5R} = \frac{36}{5}\times 91 = 655.2$ nm
4. $\lambda_P-\lambda_B = 1216.8 \approx 1217$ nm
5. So the answer is (c) 1217.