When a certain photosensitive surface is illuminated with monochromatic light of frequency , the stopping potential for the photo current is
. When the surface is illuminated by monochromatic light of frequency
, the stopping potential is
. The threshold frequency for photoelectic emission is :
2
Stopping Potential /Cut-off Potential -
It is defined as the potential necessary to stop any electron from reaching the other side.
-
For v frequency stoping potential is
For frequency stoping potential is -v0
So for frequency
For frequency
From 1 and 2
We get
so
2
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