Write the experimental observations of Photoelectric effect.
(1) For a given metal, there exists a certain minimum frequency above which the photoelectric effect takes place which is known as threshold frequency.
(2) Maximum kinetic energy of the emitted photoelectrons increases as the frequency of the incident light is increased keeping the number of incident photons to be fixed.
(3) Above threshold frequency, maximum kinetic energy of the photoelectrons depends only on the frequency of incident light but is independent of the intensity of incident light.
(4) For a given metal and frequency of incident light, the rate at which the photoelectrons ejected is directly proportional to the intensity of incident light. An increase in the magnitude of the incident light increases the magnitude of the photoelectric current.
(5) The time lag between the incidence of photons and radiation of photoelectric effect is very small, nearly 10−9 second.