When an unpolarised light of intensity I gets polarised on passing through a polaroid, what will be the intensity ?

\(\frac{I}{4}\) \(\frac{I}{2}\) \(\frac{I}{\sqrt { 2}}\) depends upon the angle of polaroid.

\(\frac{I}{2}\)

Average intensity : <I> = Io <cos2\(\theta \)> <cos2\(\theta \)> = \(\frac{1}{2}\)