# Formula Photoelectric effect (cutoff frequency, work function)

## Cutoff frequency

Unit
Cutoff frequency is the minimum frequency that light must have in order to be able to knock electrons out of a material.

## Work function

Unit
Work function is the energy that must be absorbed to eject an electron from a solid (e.g. from a metal plate). As a rule, the work function is given in the unit "eV" (electron volt):$$1 \, \mathrm{eV} = 1.6 \cdot 10^{-19} \, \mathrm{J}$$

## Planck's constant

Unit
Planck's constant is a natural constant that appears in the equations when the phenomenon under consideration exhibits quantum mechanical behavior. The Planck's constant has the value: $$h ~=~ 6.626 \cdot 10^{-34} \, \mathrm{Js}$$