Definition:Planck's Constant

Definition
Planck's constant is the physical constant $h$ which defines the quantum nature of energy and relates the energy of a photon to its frequency.

Thus:
 * $E = \dfrac h f$

where:
 * $E$ denotes the energy of a photon
 * $f$ denotes the frequency of that photon
 * $h$ denotes Planck's constant.

It is used for describing the behaviour of particles and waves at an atomic scale. Planck's constant also occurs in Heisenberg's uncertainty principle.

Physical quantities with the same dimension include angular momentum and action.

Also see

 * Definition:Reduced Planck Constant