Module 5 : MODERN PHYSICS
Lecture 24 : Photoelectric Effect
  The photoelectric effect exhibits the following features :
Photoelectrons are not ejected unless the frequency of incident light is above a certain threshold value
  $ \nu_{th}$. The value of $ \nu_{th}$ depends on the material of the cathode.
If the frequency of incident radiation $ \nu$ is greater than $ \nu_{th}$, even a light of very weak intensity will cause
photoelectrons to be emitted. If $ \nu <\nu_{th}$, even the most intense light will not cause photoelectrons to be emitted. For $ \nu >\nu_{th}$ , the photo-current increases linearly with the intensity of light.
 
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