When light of an unknown polarisation is examined with a polaroid, it is found to exhibit maximum intensity `I_(0)` along y-axis and minimum intensity `(2 I_(0))/3` along x-axis. The intensity transmited through a polaroid with pass axis at `45^(@)` to y-axis (in x-y plane) is

Options

A. `5/8 l_(0)`
B. `l_(0)/2`
C. `5/6 l_(0)`
D. `l_(0)/4`

Answer

C

Explanation

Given, maximum intensity along y-axis,
`I_(Y)=I_(0)`
and minimum intensity along x-axis,
`I_(X)=(2I_(0))/3`
The intensity transmitted, through a polaroid with pass axis `45^(@)` to y-axis (i.e., `45^(@)` to x-axis also) is given by Brewster's law,
`I=I_(x) cos^(2) 45^(@)+I_(y) cos^(2) 45^(@)`
`=I_(0)cos^(2) 45^(@)+(2I_(0))/3 cos^(2) 45^(@)`
`=I_(0). 1/2+(2I_(0))/3.1/2=I_(0)/2+I_(0)/3=(5I_(0))/6`