Question

Unpolarized light passes through a combination of two ideal polarizers. The transmission axes of the first polarizer and the second polarizer are at 30.0° to each other. What percentage of the original light gets through the combination?

Answer 1

62.5 %

Step-by-step explanation:

Let the initial intensity of unpolarized light is Io.

After first polariser the intensity of light becomes I'.

So,
`I' = (I_(0))/(2)`

Now it passes through another polariser. The angle between the first polariser and the second polariser is given by Ф. The intensity is I''.

According to the law of Malus

`I'' = I' Cos^(2)\phi`

Here, Ф = 30 degree

`I'' = (I_(0))/(2) Cos^(2)30=0.375I_(0)`

The percentage change in the intensity is given by

`(I_(0)-I'')/(I_(0))* 100=(I_(0)-0.375I_(0))/(I_(0))*100`

= 62.5 %