Answer
The hydrogen atom is excited to the third energy level.
Work Step by Step
We can find the new energy of the hydrogen atom:
$E_f = E_0+12.1~eV$
$E_f = (-13.6~eV)+12.1~eV$
$E_f = -1.5~eV$
We can find the new energy level:
$E_f = \frac{E_0}{n^2}$
$n^2 = \frac{E_0}{E_f}$
$n = \sqrt{\frac{E_0}{E_f}}$
$n = \sqrt{\frac{-13.6~eV}{-1.5~eV}}$
$n = 3.0$
The hydrogen atom is excited to the third energy level.
