Unpolarized light of intensity I passes through an ideal polariser A . Another identical polariser B is placed behind A . The intensity of light beyond B is found to be I 2 . Now another identical polariser C is placed between A and B . The intensity beyond B is now found to be I 8 . The angle between polariser A and C is

Step-by-step solution

Transformation axis A and B are parallel. If the transformation axis of C is making angle θ with A , it will make angle 90 − θ with B . Therefore, ⇒ I 2 cos 2 θcos 2 ( 90 − θ ) = I 8 ⇒ 1 4 sin 2 2 θ = 1 4 ⇒ 2 θ = π 2 ⇒ θ = π 4