The shortest wavelength of H – atom in Lyman series is x, longest wavelength In Balmer series of He+ is

Shortest wavelength means maximum wave number where n2 = ∞For the shortest wavelength of H-atom in Lyman series,n1 = 1 and n2 = ∞Longest wavelength means minimum wave number, Where n2 = n1 +1Thus in Balmar series of He+  n1 = 2 and n2 = 2 + 1 = 3; Z = 2Substituting (1) in (2)