## College Physics (4th Edition)

$K = 11.6~eV$
We can find the energy when the atom is in the n=2 state: $E = \frac{E_0}{n^2}$ $E = \frac{-13.6~eV}{2^2}$ $E = -3.4~eV$ The energy required to remove the electron from the atom is $3.4~eV$. We can find the kinetic energy of the electron after it is removed from the atom: $K = 15.0~eV-3.4~eV = 11.6~eV$