What is photoelectric effect?

Explanation

Einstein.s Photoelectric equation is
`1/2 mv^2 = h(v - v_0)`
We can explain the laws of photoelectric emission with its help as follows:
1. The photoelectrons will possess positive kinetic energy and hence will be ejected out of surface, only if `v gt v_0` i.e. if the frequency of incident radiation is greater than the threshold frequency for the metal.
2. The photoelectrons will come out of the metal surface with greater value of maximum kinetic energy `(1/2 mv_("max")^2 = hv - hv_0)`, as the frequency of incident radiation is increased.
3. The number of photoelectrons ejected will be large, when intense radiation is incident. This is because, an intense radiation will contain a large number of photons and photoelectric effect is a one photon-one electron phenomenon i.e. one photon is capable of ejecting only one electron.