Unpolarized light of intensity 32 `Wm^(-3)` passes through three polarizers such that the transmission axis of the last polarizer is crossed with the first. If the intensity of the emerging light is `3 Wm^(-2)`, what is the angle between the transmission axces of the first two polarizers ? At what angle will the transmitted intensity be maximum ?

Options

A. `60^(@)`
B. `45^(@)`
C. `90^(@)`
D. `120^(@)`

Answer

A

Explanation

`I_(2)=I_(1)cos^(2)(90^(@)-theta)=(I')/2cos^(2)thetasin^(2)theta=(I')/8(sin2theta)^(2)`

`3=32/8(sin 2theta)^(2)`
`sin 2theta=sqrt(3)/2=sin 60^(@)or sin 120^(@)`
`theta=30^(@)or 60^(@)`