Hydrogen (1H1), deuterium (1H2), singly ionised helium (2He4)+ and doubly ionised lithium(3Li8)++ all have one electron around the nucleus. Consider an electron transition from n=2 to n=1 . If the wavelength s of emitted radiation are λ1,λ2,λ3 and λ4, respectively for four elements, then approximately which one of the following is correct?