The ionisation potential of hydrogen atom is 13.6 volt. The energy required to remove an electron in the n = 2 state of the hydrogen atom is

27.2 eV 13.6 eV 6.8 eV 3.4 eV

3.4 eV

Energy required to remove electron in the n = 2 state = $+\frac{13.6}{(2)^2}$ = +3.4 eV