Formula Photoelectric effect Work function Frequency Stopping voltage Planck's constant
$$W ~=~ h \, f ~-~ e \, U_{\text G}$$ $$W ~=~ h \, f ~-~ e \, U_{\text G}$$ $$f ~=~ \frac{W ~+~ e \, U_{\text G}}{h}$$ $$U_{\text G} ~=~ \frac{h \, f ~-~ W}{e}$$ $$e ~=~ \frac{h \, f ~-~ W}{U_{\text G}}$$ $$h ~=~ \frac{W ~+~ e \, U_{\text G}}{f}$$
Work function
\( W \) Unit \( \mathrm{J} \) 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
\( f \) Unit \( \mathrm{Hz} \) Frequency of the light with which, for example, a metal plate is illuminated.
Stopping voltage
\( U_{\text G} \) Unit \( \mathrm{V} \) 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
\( e \) Unit \( \mathrm{C} \) 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
\( h \) Unit \( \mathrm{Js} \) Planck's constant is a physical constant and has the value:$$ h ~=~ 6.626 \, 070 \, 15 \, \cdot \,10^{-34} \, \mathrm{Js} $$