E_{n} = −13.6 eV \frac{1}{n^{2}}

E(photon) = hν = \frac{hc}{λ} = E_{f} − E_{i} = (−13.6 eV))(\frac{1}{n_{f}^{2}} − \frac{1}{n_{i}^{2}} )

\frac{N_{b}}{N_{a}} = (\frac{g_{b}}{g_{a}})(e^{−(E_{b}−E_{a})/kT})

KE_{typ} ≃ kT