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

Answer

A

Explanation

According to Malus law,
`I=I_(0)cos^(2)theta`
Here, `I=(I_(0))/(2)`
Now, `(I_(0))/(2)=I_(0)cos^(2)theta`
`rArr cos^(2)theta = (1)/(2)`
`rArr cos theta = (1)/(sqrt(2))`
`rArr theta = "cos"^(-1)(1)/(sqrt(2))=45^(@)`