# Law Of The Photoelectric Emission And Einstein’s Explanation

## Photoelectric Emission:

In an atom electron are strongly bounded to their nucleus. To remove these electron we have to over come the strong forces of attraction for which we need energy which is called as Work Function.

If the electron emission from the surface of metal takes with the help of light radiations of very high frequency then it is called as Photoelectric Emission.

# Law Of Photoelectric Emission:

1) For a given metal and frequency the photoelectric current is directly proportional to the intensity of incident radiations.

2) There exit a certain minimum value of frequency below which photoelectric emission can’t takes place.

3) Above Threshold frequency the kinetic energy of the emitted electron isdirectly proportional to the frequency of the incident radiation.

4) Photoelectric is an instantaneous process the time lack between incidence of radiation and emitter of Photo electrons is 10-8 second.

## Einstein Photoelectric Equation:

Einstein used Plank’s Quantum Theory to explain the laws of the photoelectric effect. According to the Einstein light radiations are made up of photons. And the each of the photon is required to eject the electrons from the surface of the metal. The total energy of the photon is used in to two ways first to eject the electrons from the surface of the metal and secondly to provide the kinetic energy to the ejected electrons.

Energy Associated with photon of the light is equals to the E = h μ

If the w is the work done and μo threshold frequency then W = h μo

### Statements Of Albert Einstein For the Explanation Of The Laws Of Photoelectric Effect:

1) According to the Albert Einstein For a given metal and frequency when the frequency of the incident radiations increased the number of the photons falling per unit in the surface of the metal increases as one photon is required to eject the one electron. So, therefore the number of the photoelectrons ejected from the surface of the metal increases and Hence the photoelectric Current increases.

### 2)     If   μo < μ

Then the value of the photoelectric current will be Negative Which Can’t be possible. So, Einstein Gives Another Law for his explanation i.e.

So, Therefore applied Frequency should be greater then the threshold frequency in order to cause the Photoelectric Emission.

So,

### ½  m V 2 = h μ

Where the kinetic energy is directly proportional to the the μ

4) The photoelectric is an outcome of the elastic collision between the photons and the electrons Whole of the energy is transfer to the electrons directly as the process of the elastic collision which is very fast, So, therefore there is not any time lack between the incident radiations and the photoelectric emission of the electrons from the surface of the metal.

So, these are the statements which are given the Albert Einstein For the Explanation of the Photoelectric Emission.