the ground stste energy of H- atom is -13.6 eV. the energy needed to ionise H- atom from its second excited state is

Question

1.51 eV
3.4 eV
13.6 eV
12.1 eV

Answer 1

That state is 13.6 eV/(2^2) = 3.4 eV below the ionization limit, since the principal quantum number is 2.