Light falls on a metal, each photon of which has an energy of $h\nu = 4$ eV. The work function of this metal is $A = 2$ eV. Find the maximum kinetic energy of the photoelectrons.
Einstein's photoelectric equation:
$$E_k = h\nu - A = 4 - 2 = 2 \text{ eV}$$
$E_k = 2$ eV