Formula: Photoelectric Effect Energy Frequency
$$W ~=~ h \, \class{red}{f_0}$$
$$W ~=~ h \, \class{red}{f_0}$$
$$\class{red}{f_0} ~=~ \frac{W}{h}$$
$$h ~=~ \frac{W}{ \class{red}{f_0} }$$
Work function
$$ W $$ Unit $$ \mathrm{J} = \mathrm{Nm} = \frac{ \mathrm{kg} \, \mathrm{m^2} }{ \mathrm{s}^2 } $$
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):
$$ 1 \, \mathrm{eV} = 1.6 \cdot 10^{-19} \, \mathrm{J} $$
Cutoff frequency
$$ \class{red}{f_0} $$ Unit $$ \mathrm{Hz} = \frac{ 1 }{ \mathrm{s} } $$
Cutoff frequency is the minimum frequency that light must have in order to be able to knock electrons out of a material.
Planck's Constant
$$ h $$ Unit $$ \mathrm{Js} = \frac{ \mathrm{kg} \, \mathrm{m}^2 }{ \mathrm{s} } $$
Planck's constant \( h \) is a physical constant from quantum mechanics and has the following exact value:
$$ h ~=~ 6.626 \, 070 \, 15 ~\cdot~ 10^{-34} \, \mathrm{Js} $$