Two polaroids are oriented with their planes perpendicular to incident light and transmission axis making an angle of `30^(@)` with each other. What fraction of incident unpolarised light transmitted?

Explanation

`I^(')`: intensity of unpolarised light
`I^(')/2`: intensity of polarised light
`I`: intensity of emergent light
`I=I^(')/2 cos^(2) 30^(@)=I^(')/2xx3/4=(3I)/8`
`I/I^(')=3/8 i.e. 300/8=37.5%`