Question

A narrow beam of unpolarised light of intensity `I_(0)` is incident on a polaroid `P_(1)`. The light transmitted by it is then incident on a second polaroid `P_(2)` with its pass axis making an angle of `60^(@)` to the pass axis of `P_(1)`. Find intensity of light transmitted by `P_(2)`.

Answer 1

Intensity of transmitted light polarised by `P_(1)` is `I_(1) = I_(0)//2`.
As `theta = 60^(@)`, therefore according to Law of Malus, intensity of polarised light transmitted by `P_(2)`
is `I_(2) = I_(2) cos^(2) 60^(@) = (I_(0))/(2)((1)/(2))^(2) = (I_(0))/(8)`