Two polaroids are placed in the path of unpolarized beam of intensity `I_(0)` such that no light is emitted from the second polarid. If a third polaroid whose polarization axis makes an angle `theta` with the polarization axis of first polaroid, is placed between these two polariods then the intensity of light emerging from the last polaroid will be

Options

A. `(I_(0)/8)sin^(2)2theta`
B. `(I_(0)/4)sin^(2)2theta`
C. `(I_(0)/2)cos^(4)theta`
D. `I_(0)cos^(4)theta`

Answer

A

Explanation

`I=[(I_(0)/2)cos^(2)theta]cos^(2)(90^(@)-theta)`
= `I_(0)/2cos^(2)thetasin^(2)theta=I_(0)/8sin^(2)2theta`