# The frequency of radiation emitted when the electron falls from n = 4 to n = 1 in a hydrogen atom will be (Given ionization energy of $H = 2.18\times 10^{-18} J atom^{-1}$ and $h=6.625\times 10^{-34} Js$):
( A ) $2.00\times10^{15} s^{–1}$
( B ) $3.08\times 10^{15} s^{-1}$
( C ) $1.54\times10^{15} s^{–1}$
( D ) $1.03\times 10^{15} s^{–1}$