According to wave theory:
(i) The maximum kinetic energy o.f the emitted electron'should be directly proportional to the intensity of incident radiations, but it is not observed experimentally. Also the maximum kinetic energy of the emitted electrons should not depend upon incident frequency according to wave theory, but it is not so.
(ii) Electron emission should take place at all frequencies of radiations, i.e. there should not exist the threshold frequency, This fact contradicts experimental observation.
(iii) There should be a time lag in photo electric emission but according to observation photo electric emission is instantaneous.
