Given below are two statements :

Statement I : If the Brewster's angle for the light propagating from air to glass is $$\mathrm{\theta_B}$$, then the Brewster's angle for the light propagating from glass to air is $$\frac{\pi}{2}-\theta_B$$

Statement II : The Brewster's angle for the light propagating from glass to air is $${\tan ^{ - 1}}({\mu _\mathrm{g}})$$ where $$\mathrm{\mu_g}$$ is the refractive index of glass.

In the light of the above statements, choose the correct answer from the options given below :

An unpolarised light beam of intensity $$2 I_{0}$$ is passed through a polaroid P and then through another polaroid Q which is oriented in such a way that its passing axis makes an angle of $$30^{\circ}$$ relative to that of P. The intensity of the emergent light is

Light enters from air into a given medium at an angle of $$45^{\circ}$$ with interface of the air-medium surface. After refraction, the light ray is deviated through an angle of $$15^{\circ}$$ from its original direction. The refractive index of the medium is:

The power of a lens (biconvex) is $$1.25 \mathrm{~m}^{-1}$$ in particular medium. Refractive index of the lens is 1.5 and radii of curvature are $$20 \mathrm{~cm}$$ and $$40 \mathrm{~cm}$$ respectively. The refractive index of surrounding medium: