How does one explain the emission of electrons from a photosensitive surface with the help of Einstein's photoelectric equation?

In photoelectric effect, an electron from a photosensitive surface, absorbs a quantum of electromagnetic radiation energy (hν). If this energy absorbed exceeds the minimum energy needed for the electron to escape from the photosensitive surface (Work function φo), the electrons are emitted with maximum kinetic energy (kmax); kmax = hν − φo. This is Einstein's photoelectric equation.