the law that energy associated with electromagnetic radiation, as light, is composed of discrete quanta of energy, each quantum equal to Planck's constant times the corresponding frequency of the radiation: the fundamental law of quantum mechanics.
2.
the law giving the spectral distribution of radiation from a blackbody.
Also called Planck radiation formula, Planck's law.
Origin of Planck's radiation law
1905-1910
First recorded in 1905-10; named after M. K. E. Planck
(physics) a law that is the basis of quantum theory, which states that the energy of electromagnetic radiation is confined to indivisible packets (quanta), each of which has an energy equal to the product of the Planck constant and the frequency of the radiation