Question

Unpolarised light is passed through a polaroid `P_(1)`. When this poalrised beam passes through another polaroid `P_(2)`, and if the pass axis of `P_(2)` makes an angle `theta` with pass axis of `P_(1)`, then write the expression for the polarised beam passing through `P_(2)`. Draw a plot showing the variation of intensity when `theta` varies from 0 to 2 `pi`.

Answer 1

If `I_(0)` is intensity of unpolarised light, then intensity pf polarised light from `P_(1)` is
`I_(1) = I_(0)//2`
When this is passed through another polaroid `P_(2)`, intensity of polarised light from `P_(2)` is
`I_(2) = I_(1) cos^(2) theta`
When `theta` is varied from `0 to 2 pi`, we obtain `I_(2)` versus `theta` plot as shown in Fig.