Photoelectric Effect

where

is a constant energy (depends on particular metal)
is the constant of proportionality
is angular velocity

Einstein-Planck Relation

where is the energy of the light of angular frequency existing in small packets

Energies of Hydrogen Atom

where and is the Rydberg’s Constant

De Broglie's Relations

Suppose there is a free particle of energy and momentum with wave of angular frequency and wave vector

de Broglie relations are