1) Photoelectric effect is an instantaneous effect. (as time lag is 10-9 second)
2) For a photometal there is a minimum frequency of incident radiation below which there is no photoelectric effect, this minimum frequency is called 'threshold frequency (v0)'.
3) Above threshold frequency, kinetic energy of photoelectrons is directly proportional to the frequency of incident radiation. (Κ.Ε αυ)
4) Above threshold frequency, number of photoelectrons (and hence photoelectric current) is directly proportional to the intensity of incident radiation.
5) Above threshold frequency, there is a minimum negative potential of the anode for which photoelectric current becomes zero. This minimum negative potential of anode is called as "stopping potential" or "retarding potential".
