Formula Photoelectric effect (cutoff frequency, work function)
$$\class{red}{f_0} ~=~ \frac{W}{h}$$ $$\class{red}{f_0} ~=~ \frac{W}{h}$$ $$W ~=~ h \, \class{red}{f_0}$$ $$h ~=~ \frac{W}{ \class{red}{f_0} }$$
Cutoff frequency
\( \class{red}{f_0} \) Unit \( \mathrm{Hz} \) Cutoff frequency is the minimum frequency that light must have in order to be able to knock electrons out of a material.
Work function
\( W \) Unit \( \mathrm{J} \) 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
\( h \) Unit \( \mathrm{Js} \) 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: $$ h ~=~ 6.626 \cdot 10^{-34} \, \mathrm{Js} $$