The energy required to excite an electron from n = 2 to n = 5 in a hydrogen atom is 4.896 × 10⁻¹⁹ J. What is the wavelen
λ = hc/ΔE ≈ 406.1 nm.
Ref: NCERT Class 11 Chemistry > Chapter 2: Structure of Atom > Topic: Developments Leading to Bohr Model - Electromagnetic Radiation and Spectrum