COMPTON EFFECT

When x- rays of wavelength 'λ' struck a sample of graphite, an electron was ejected and the x- rays scattered at angle θ had longer wavelength λ.

Explanation of Compton effect :-

   

                                        Compton said that it was like a ball hitting a stationery ball which is pushed away while the energy of the striking ball decreases.

                                   he was argued that light radiation (x- rays) consisted of particles (photons) as a continuous wave could not have knocked out the electron.

            " He visualised that the proton of incident light stuck a stationary electron in graphite (carbon) and hence lost some energy which resulted in the increase of wavelength"

                   This process won't have occurred unless light radiation consisted of particles or photons.

Compton scattering of x- rays :-

By assume is the photon - electron collisions to be perfectly elastic, Compton found that the shift in wavelength, dλ  was given by the expression, 

           dλ =  2h   sin² θ/2

                    mc

Where, 

             h - plank's constant 

             m- mass of an electron 

             C - velocity of light 

             θ - angle of scattering 

The expression shows that dλ is independent of the nature of the substance and wave length of the incident radiation. 

  

                  Given the wavelength of a photon one we can calculate the momentum of the electron ejected.