Unpolarized light of intensity I passes through an ideal polarizer A. Another identical polarizer B is placed behind A. The intensity of light beyond B is found to be `(1)/(2)` . Now another identical polarizer C is placed between A and B. The intensity beyond B is now found to be `(1)/(8)`. The angle between polarizer A and C is ......

Options

A. `0^(@)`
B. `30^(@)`
C. `45^(@)`
D. `60^(@)`

Answer

D

Explanation

The intensity of light coming from plate A `(1)/(2)` is Which is also the intensity of light coming from C (intensity before B) is `(1)/(2)`
`:.` The intensity of light coming from C,
`:.(I)/(8)=(I)/(2) cos^(2) theta`
`:.(I)/(4)=cos^(2) theta`
`:. (I)/(2)= cos^(2) theta`
`:. theta=6^(@)`