Einstein’s Photoelectric Equation

According to Planck’s Quantum theory, light radiations consists of tiny packets of energy called quanta.

One quantity of light radiation is called a photon which travels with the speed of light.

The energy of a Photon is  E= hv

Where h is Planck’s Constant and is frequency of light radiation.

When a photon of energy fall on a metal surface, the energy of photon is absorbed by the electron and is used in following two ways.

(I) A part of energy is used to overcome the surface areas and electron comes out of the metal surface this part of energy is called work function (Ø) and Ø₀= hv

(II) The remaining part of the energy is used in giving a velocity to the photoelectron. This is equal to the maximum kinetic energy of photoelectron.


* If v<v₀, no emission will take place.

* If v= v₀, emission will take place but photo electron have no any kinetic energy.

* If v>v₀, emission will take place.



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