# What is the relationship between the energy differences of the orbits in an atom and the light emitted by the atom?

When an electron makes a transition from a level of higher energy ${E}_{h}$ to a level of lower energy ${E}_{l}$, then it emits a single photon of frequency,
$\nu = \frac{{E}_{h} - {E}_{l}}{h}$ where $h$ is the Planck's constant.