If the angle between the polarizer and the analyser is increased from 30 degrees to 60 degrees, how will the intensity vary ?

It will increase exactly by a factor of 3 It will remain constant It will decrease exactly by a factor of 3 It may increase or decrease depending upon the nature of the analyser.

It will decrease exactly by a factor of 3

By I = Io Cos2\(\theta \) ,  $I_1 =  I_0 \frac{3}{4}$ $I_2 = I_0 \frac{1}{4} = \frac{I_1}{3}$