# Planck Constant

on . Posted in Relativity

Planck constant, abbreviated as h, is a physical constant that relates the energy of one photon of electromagnetic waves to the frequency of that wave used in classic mechanics and quantum mechanics.  Planck units are based on physical constants rather than human scales.  The significance of the Planck constant arises in the context of Planck's law, which describes the spectral distribution of electromagnetic radiation emitted by a black body.  It also plays a central role in Heisenberg's uncertainty principle, which states that there is a fundamental limit to the precision with which certain pairs of properties, such as position and momentum, can be simultaneously known.

### Planck Constant Formula

$$E = h \; f$$     (Planck Constant)

$$h = E \;/\; f$$

$$f = E \;/\; h$$

Symbol English Metric
$$E$$ = energy (See Physics Constant) $$lbf-ft$$   $$J$$
$$f$$ = frequency $$Hz$$ $$s{-1}$$
$$h$$ = Planck constant $$lbf-ft \;/\; sec$$  $$J-s$$