Radiation energy is built up of discrete units – the
so called quanta of energy of radiation Each quantum of radiant energy
has energy hn, where h is Planck’s constant and n the frequency of light In photoelectric effect, an electron absorbs a quantum of energy (hn ) of
radiation If this quantum of energy absorbed exceeds the minimum
energy needed for the electron to escape from the metal surface (work
function f0), the electron is emitted with maximum kinetic energy
Kmax = hn – f0
(11