A hydrogen atom initially in the ground level absorbs a photon, which excites it to $n=4$ level. Determine the wave length and frequency of photon .

Question

$\begin{array}{1 1} \lambda= 97 \times 10^{-8} \;m; \alpha =31 \times 10^{15}Hz \\ \lambda= 0.97 \times 10^{-8} \;m; \alpha =0.31 \times 10^{15}Hz \\ \lambda= 9.7 \times 10^{-8} \;m; \alpha =31 \times 10^{15}Hz \\ \lambda= 9.7 \times 10^{-8} \;m; \alpha =3.1 \times 10^{15}Hz\end{array} $