(a) Light consists of photons. When a photon inferacts with an electron it gives its entire energy to the electron and then exists no longer. Energy used to knock out the electron. (hv) is work function and rest energy is given to electron is kE.
(b) (i) Greater intensity has no effect on kE of an electron cannot be explained by wave theory.
(ii) Wave theory also fails to explain the existence of threshold energy.
