The ratio of maximum to minimum wavelength in Balmer series of an hydrogenic atom is

Step-by-step solution

Wavelength of spectral lines of Hydrogen like atom is given as 1 =R ( 1 n₁^2 - 1 n₂^2 ) For Balmer series, n₁=2 and n₂=3,4,5,6, . For minimum wavelength, n₂= From Eq. (i), 1 _ =R ( 1 2^2 - 1 ^2 ) For maximum wavelength, n₂=3 From Eq. (i), we have From Eq. (ii) and (iii), we have _ _ = 36 / 5 R 4 / R = 36 20 = 9 5