Formula: Photoelectric Effect Energy Cutoff wavelength
$$W ~=~ h \, \frac{c}{\class{red}{\lambda_0}}$$
$$W ~=~ h \, \frac{c}{\class{red}{\lambda_0}}$$
$$\class{red}{\lambda_0} ~=~ h \, \frac{c}{W}$$
$$h ~=~ \frac{ \class{red}{\lambda_0} \, W}{c}$$
$$c ~=~ \frac{ \class{red}{\lambda_0} \, W}{h}$$
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 expended to knock an electron out of a solid (e.g. out of a metal plate). Usually, the work function is given in the unit "eV" (electron volt):
$$ 1 \, \mathrm{eV} = 1.6 \cdot 10^{-19} \, \mathrm{J} $$
Cutoff wavelength
$$ \class{red}{\lambda_0} $$ Unit $$ \mathrm{m} $$
Cutoff wavelength is the minimum wavelength that light must have in order to be able to knock electrons out of a metal plate.
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:
$$ h ~=~ 6.626 \, 070 \, 15 ~\cdot~ 10^{-34} \, \mathrm{Js} $$
Speed of light
$$ c $$ Unit $$ \frac{\mathrm m}{\mathrm s} $$
Speed of light is a physical constant and indicates how fast light travels in empty space (vacuum). It has the following exact value in vacuum:
$$ c ~=~ 299 \, 792 \, 458 \, \frac{ \mathrm{m} }{ \mathrm{s} } $$