Given that, ionisation potential of hydrogen atom, E1=â13.6âeV Energy supplied = Energy absorbed by hydrogen atom. ÎE=12.1âeV i.e. final energy of excited state, E2=
â13.6âeV
n2
We know that, E2âE1=ÎEâE2=ÎE+E1 Substituting the value, we get â
13.6
n2
=[12.1+(â13.6)] ââ
13.6
n2
=â1.50âx2=9.07ânâ3 Hence, by absorbing 12.1 eV energy electron jump into 2nd excited state (n=3). Then, number of spectral lines emitted by H-atom =