The ratio of the wavelengths of the first lines in the Lyman and Balmer series of a hydrogen atom is: (RH = 1.097 × 10⁷
λLyman/λBalmer ≈ 0.185.
Ref: NCERT Class 11 Chemistry > Chapter 2: Structure of Atom > Topic: Electronic Configuration - Aufbau Pauli Hund and Stability