Write any three experimental observations of photoelectric effect

Explanation

(i) Photoemission is instantaneous.
(ii) For every photo emissive surface there is a minimum frequency of the incident radiation below which there is no photo emission. This minimum frequency is called threshold frequency.
(iii) For frequency greater than threshold, the strength of the photo electric current is directly proportional to the intensity of the incident radiation.
(iv) The maximum K.E of the photo electrons increases linearly with the frequency of the incident radiation.
(v) There exists a minimum -ve potential called stopping potential for which anode repels the electrons completely.