A sample of atomic hydrogen gas is irradiated by a beam of ultraviolet radiation having a wavelength between 100 nm and 200 nm . Assuming that the atoms are in the ground state, the wavelength which will have low intensity in the transmitted beam is

Step-by-step solution

The energy of a photon corresponding to λ = 100   nm is, 1 2 4 2 eV nm 1 0 0 nm = 1 2 · 4 2   eV Similarly, the corresponding to λ   =   200   nm is 6 . 21   eV . The energy needed to take the atom from the ground state to the first excited state is E 2 - E 1 = 13 . 6   eV - 3 . 4   eV = 10 . 2   eV The energy needed to take the atom from the ground state to the second excited state is E 3 - E 1 = 13 . 6   eV - 1 . 5   eV = 12 . 1   eV