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 $$ \mathrm{C} = \mathrm{As} $$ 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 $$ \mathrm{Js} = \frac{ \mathrm{kg} \, \mathrm{m}^2 }{ \mathrm{s} } $$ Planck's constant is a physical constant and has the value:$$ h ~=~ 6.626 \, 070 \, 15 \, \cdot \,10^{-34} \, \mathrm{Js} $$