The shortest wavelength of hydrogen atom in Lyman series is λ. The longest wavelength in Balmer series of He+ is [2023]
(1)
(1) For Hydrogen atom (Z=1):
(1λ)H=RH(1)2[112-1∞2]→Last line
(2) For He+ atom (Z=2):
(1λ)He+=RH(2)2[122-132]=RH[1-49]
=RH(59)→first line
From (1) and (2)
λHe+λH=95
λHe+=9λH5