State laws of photoelectric emission.

Explanation

Laws of Photoelectric emission are :
1. For a given metal and frequency of incident radiation, the no. of photoelectrons emitted per second is directly proportional to intensity of incident light.
2. For a given metal, there exists a certain minimum frequency of incident radiation below which no emission of photoelectrons takes place. This frequency is called threshold frequency `(upsilon_(0))` For every substance, the value of threshold frequency is
different.
3. The process of photoelectric emission is an instantaneous process.
4. Above the threshold frequency, the maximum kinetic energy of emitted photoelectron is independent of intensity of incident light. But themaximum kinetic energy of photo-electrons increases with increase in the frequency of the incident light, provided the frequency of incident light is greater than the threshold frequency.