Q.13:- What is the wavelength of light emitted when the electron in a hydrogen atom undergoes transition from an energy level with n = 4 to an energy level with n = 2?
Answer:-
ṽ = R(1/n12 – 1/n22) = 109677(1/22 – 1/42) cm-1 = 20564.4 cm-1
λ = 1/ν = 1/20564.4 = 486×10-7 cm = 486×10-9 m = 486 nm