Unplarised light is passed through a polaroid `P_(1)`. When this polarised beam passes through another polaroid `P_(2)` and if the pass axis of `P_(2)` makes angle `theta ` with the 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 `2pi`.

Explanation

Let the intensity of unpolarised light incident on `P_(1)` be `I_(0)`. Then the intensity of light
transmitted by `P_(1) = (I_(0))/(2)`
Applying Malus' law, the intensity of light transmitted
by ` P_(2) = (I_(0))/(2) cos^(2)theta`