Two polaroids are kept crossed to each other. Now one of them is rotated through an angle of 45⁰. The percentage of incident light now transmitted through the system is (ans:25%)

Let intensity be i.On passing through first Polaroid intensity reduces to half i.e i/2. On passing through second Polaroid intensity can be found by using malus law. I new = i/2cos^(phi/2) Given phi =45° I new = i/2(1/✓2)^2 I new = i/4. Now percentage of incident light transmitted is (1/4)100= 25%

two polaroids are kept crowe weah other, one of them is rotated through an angle of 45 the percentage of incident light now transmitted through the system is