Planck's lawPlanck's law
, discovered by Max Planck
, is the basis of the quantum theory
The law states that the energy associated with electromagnetic radiation comes in indivisible packets called quanta, each of which is associated with a single photon. The size (E) of a quantum depends on the frequency (f) of the radiation, according to the formula
- E = hf,
is Planck's constant
Using SI units, energy is measured in joules, frequency is measured in in hertz, and Planck's constant has the unit joule seconds.