Assertion: A spherical wavefront is produced by a point source of light.

Reason: It is because, the locus of all points, which are equidistant from the point source, is a sphere.

Except for polished surfaces, ${\tan }^{-1}\left(\mathrm{\mu }\right)$ in Brewster's law depends upon which of the following?

Unpolarized light is incident from air on a surface of material of refractive index $\sqrt{3}$ at Brewster's angle. The angle of refraction is: