Skip to main content

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

Formula: Photoelectric Effect
Capacitor with set stopping voltage for photoelectric effect
Hover the image! Get this illustration

Work function

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

Stopping voltage

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

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

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