A `12.5 eV` electron beam is used to excite a gaseous hydrogen atom at room temperature. Determine the wavelengths and the corresponding series of the lines emitted.

Explanation

In ground state, energy of gaseous hydrogen at room temperature `=-13.6eV.` When it is bombarded with 12.5 eV electron beam, the energy becomes `-13.6+12.5=-1.1eV`. The electron would jump form n=1 to n=3, where `E_3=-13.6/(3^2)=-1.5eV`. On de-excitation the electron may jump form n=3 to n=2 giving rise to Balmer series. It may also jump form n=3 to n=2 giving rise to Balmer series. It may also jump form n=3 to n=1, giving rise to Lyman series,