In a system of two crossed polarisers, it is found that the intensity of light from the second polariser is half from that of first polariser. The angle between their pass axes is

Options

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

Answer

C

Explanation

Given : 1 - 50% of `I_(0) = (I_(0))/(2)`
If the pass axis of `P_(2)` makes an angle `theta` with the pass axis of `P_(1)`, then
`I = I_(0)cos^(2)theta` (By Malus' law)
`therefore I_(0)//2= I_(0)cos^(2)theta`
or `cos^(2)theta= (1)/(2)` or `costheta= (1)/(sqrt(2))` or `theta= 45^(@)`