# Formula Photoelectric Effect Work function    Frequency    Stopping voltage    Planck's Constant

## Work function

Unit
Work function is the energy that must be spent to eject an electron from a solid (e.g. from a metal plate). It is usually expressed in units of "eV" (electronvolt).

## Frequency

Unit
Frequency of the light with which, for example, a metal plate is illuminated.

## Stopping voltage

Unit
Back voltage is the voltage between two capacitor plates. This voltage is adjusted so that the electrical energy $$e \, U_{\text G}$$ exactly compensates the kinetic energy of the ejected electron.

## Elementary charge

Unit
Elementary charge is the charge of the electron and has the amount: $$e = 1.602\, 176 \, 634 \, \cdot \, 10^{-19} \, \mathrm{C}$$

## Planck's Constant

Unit
Planck's constant is a physical constant and has the value:$$h ~=~ 6.626 \, 070 \, 15 \, \cdot \,10^{-34} \, \mathrm{Js}$$