or

The Planck constant, or Planck's constant, is a fundamental physical constant which is denoted by h. When a photon's frequency is multiplied by the Planck constant, it gives the energy contained in the photon. Due to mass–energy equivalence, the Planck constant also relates mass to frequency.

E=hf

Where

E is energy of photon

h is Planck's constant

f is frequency of the photon

The value of Plank's constant is 6.62 × 10-34joule second(js).