Laws of photoelectric effect
The detailed (previous Page) experimental investigations of photoelectric effect revealed the following results:
i) For a given frequency of incident light, the number of photoelectrons emitted is directly proportional to the intensity of the incident light. The saturation current is also directly proportional to the intensity of incident light.
ii) Maximum kinetic energy of the photo electrons is independent of intensity of the incident light.
iii) Maximum kinetic energy of the photo electrons from a given metal is directly proportional to the frequency of incident light.
iv) For a given surface, the emission of photoelectrons takes place only if the frequency of incident light is greater than a certain minimum frequency called the threshold frequency.
v) There is no time lag between incidence of light and ejection of photoelectrons.
Once photoelectric phenomenon has been thoroughly examined through various experiments, the attempts were made to explain it on the basis of wave theory of light.