Question

What is the energy of a photon (in joules) emitted during a transition from n_i = (5.00x10⁰) state to the n_f = (2.00x10⁰) state of the hydrogen atom?

Answer 1

Rydberg formula, $\frac{1}{\lambda}=R_H(1/n_f^2-1/n_i^2)$

$n_f=2, n_i=5$

$R_H=10973731.56816$

Energy of a photon, $E=hf=hc/\lambda=hc\times R_H(1/n_f^2-1/n_i^2)$

$E=6.626\times 10^{-34}\times 3\times 10^8\times 10973731.56816(1/2^2-1/5^2)=4.581\times 10^{-19}J$