A partially plane polarised beam of light is passes thorugh a polaroid. Show graphically the variation of transmitted light with angle of rotation of polaroid.

Explanation

As the original beam is partially polarised, `:. I = I_(unpol.) + I_(pol.)`
According to law of malus, polarised light transmitted has intebsity, `I_(1) = I_(pol.) cos^(2) theta`
`:.` Intensity of total transmitted light,
`I_(3) = I_(2) + I_(1)`
where `I_(2) =` intensity on polarization of unpolarized light.
The variation of `I_(3)` with `theta` is shown in Fig.