A transparent thin plate of a polaroid is placed on another similar plate such that the angle between their axes is `30^(@)`. The intensities of the emergent and the upolarized incident light will be in the ratio of

Options

A. `1:4`
B. `1:3`
C. `3:4`
D. `3:8`

Answer

D

Explanation

Let `I_(0)` be the intensity of unpolarized light, then intensity of light from first transparent thin plate of a polaroid is
`I=(I_(0))/(2)`
Now this light will pass through the second similar plate whose axis is inclined at an angle of `30^(@)` to that of first plate.
According to Malus law, the intensity of emerging light is
`I.=Icos^(2)30^(@)=(I_(0))/(2)((sqrt(3))/(2))^(2)=(3)/(8)I_(0),:.(I.)/(I_(0))=(3)/(8)`