Module 5 : MODERN PHYSICS
Lecture 25 : Compton Effect
The spectrum of radiation at an angle $ \theta$ consists of two peaks, one at $ \lambda_0$ and the other at $ \lambda_s$. Compton effect can be explained by assuming that the incoming radiation is a beam of particles with
 
Energy $ E=h\nu_0$
Momentum $ p=h\nu_0/c$
  In arriving at the last relationship, we use the energy - momentum relation of the special theory of relativity , according to which,
 
$\displaystyle E^2 = m^2c^4 + p^2c^2$
  where $ m$ is the rest mass of a particle. Since photons are massless ( $ m=0$), we get $ E=pc$. Compton's observation is consistent with what we expect if photons, considered as particles, collide with electrons in an elastic collision.
 

 
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