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Question
Unpolarised light is passed through a polaroid P1. When this polarised beam passes through another polaroid P2 and if the pass axis of P2 makes angle θ with the pass axis of P1, then write the expression for the polarised beam passing through P2. Draw a plot showing the variation of intensity when θ varies from 0 to 2π.
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Solution
When unpolarised light passes through the polariser P1 the intensity drops to half that is `I_o/2` and when this polarised light passes through the polariser P2 the instensity of the emitted light is
`I=I_0/2cos^2 theta`
(θ is the angle between polariser P1 and P2)
The instensity distrubution is as shown below:
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