Question

What is Einstein's explanation of photo electric effect? Explain the laws of photo electric emission on the basis of quantum nature of light

Answer 1

Dear student,

According to Einstein , the emission of the photoelectron is result of interaction between photons in incident radiation and electrons in the metal surface.When the photon of energy $h\nu$ is incident on the metal surface its energy is used in two ways
(i) A part of energy is used to remove the electron from the surface of metal because the electrons are tightly bound to nucleus.The work function of the photo metal is defined as minimum amount of energy required to remove an electron from the metal surface.
(ii)The remaining energy is used to impart kinetic energy to the liberated electrons.

Energy of the incident photon =work function+kinetic energy of the electron
$h\nu =W+\frac{1}{2}m{v}^2$
If the electron did not lose its energy due to internal collision then the entire energy will be exhibited as the kinetic energy.Thus $\left(h\nu -W\right)$ represents maximum kinetic energy of the ejected photon.If v_max is the maximum velocity with which photoelectron is ejected is
$h\nu =W+\frac{1}{2}m{v^2}_{max}$

This known as Einstein photoelectric equation.


Regards.