Consider the following spectral lines for atomic hydrogen: A. First line of Paschen series B. Second line of Balmer series C. Third line of Paschen series D. Fourth line of Bracket series The correct arrangement of the above lines in ascending order of energy is:

### Related Formula Delta E = 13.6 Z^2 left(frac1n_1^2 - frac1n_2^2right) text eV$$\Delta E = 13.6 Z^2 \left(\frac{1}{n_1^2} - \frac{1}{n_2^2}\right) \text{ eV}$$ ### Core Logic Let's find the values of n_1$n_1$ and n_2$n_2$ for each transition: - (A) Paschen (1^st$1^{st}$ line): n_1 = 3, n_2 = 4$n_1 = 3, n_2 = 4$ - (B) Balmer (2^nd$2^{nd}$ line): n_1 = 2, n_2 = 4$n_1 = 2, n_2 = 4$ - (C) Paschen (3^rd$3^{rd}$ line): n_1 = 3, n_2 = 6$n_1 = 3, n_2 = 6$ - (D) Bracket (4^th$4^{th}$ line): n_1 = 4, n_2 = 8$n_1 = 4, n_2 = 8$ Calculating or comparing the energy values corresponding to these transitions yields the ascending order of energy. ### Step 1: Final Conclusion The correct ascending order of energy of the given lines is D < A < C < B$D < A < C < B$, corresponding to option (4). ### Pattern Recognition Sees: hydrogen spectral lines energy comparison. Trap: Confusing series limits with specific line numbers. Shortcut: Evaluate transition frequencies or wavelength gaps using Rydberg formula equivalents. ### Chapter Mix Class 11 Chemistry: Structure of Atom