The expression for intensity (as shown in the figure) of transmitted light when a polaroid sheet is rotated between two crossed polaroids is:
[Given: \(I_0\) is the intensity of transmitted light from polariser A]
1. \(I = \dfrac{I_{0}}{2} \sin^{2} 2 \theta\)
2. \(I = \dfrac{I_{0}}{4} \sin^{2} 2 \theta\)
3. \(I = \dfrac{I_{0}}{2} \cos^{2} 2 \theta\)
4. \(I = \dfrac{I_{0}}{4} \cos^{2} 2 \theta\)
Unpolarised light is incident on a plane glass surface. What should be the angle of incidence so that the reflected and refracted rays are perpendicular to each other?