The energy of a photon emitted or absorbed is given by using Planck’s relation. It states that the energy of a photon, E, is proportional to its frequency, ν.
The formula for Planck’s relation between energy and frequency of radiation emitted or absorbed is given as,
E ∝ v
E = hv
E = Energy
h = Planck’s constant
v = frequency of radiation emitted or absorbed