Unpolarised light is incident from air on a plane surface of a material of refractive index $$\mu $$. At a particular angle of incidence i, it is found that the reflected and refracted rays are perpendicular to each other. Which of the following options is correct for this situation?

Young's double slit experiment is first performed in air and then in a medium other than air. It is found that 8^th bright fringe in the medium lies where 5^th dark fringe lies in air. The refractive index of the medium is nearly

The ratio of resolving powers of an optical microscope for two wavelength $$\lambda $$₁ = 4000 $$\mathop A\limits^ \circ $$ and $${\lambda _2}$$ = 6000 $$\mathop A\limits^ \circ $$ is

Two polaroids P₁ and P₂ are placed with their axis perpendicular to each other. Unpolarised light $$I$$₀ is incident on P₁. A third polaroid P₃ is kept in between P₁ and P₂ such that its axis makes an angle 45^o with that of P₁. The intensity of transmitted light through P₂ is