Wave Optics

In the List-I, four optical effects are mentioned. The physical phenomena of light which are essential to describe these optical effects are given in List-II. Choose the option which describes the correct match between the entries in List-I to those in List-II.

1. P→5, Q→4, R→1, S→3
2. P→4, Q→2, R→1, S→3
3. P→4, Q→1, R→2, S→3
4. P→5, Q→4, R→1, S→2

A point source S emits unpolarized light uniformly in all directions. At two points A and B, the ratio r=IA/IB of the intensities of light is 2. If a set of two polaroids having 45 angle between their pass-axes is placed just before point B, then the new value of r will be .