The angle of polarisation for any medium is $60^{\circ}$. What will be the critical angle for this medium?

When an unpolarized light falls at a particular angle on a glass plate (placed in air), it is observed that the reflected beam is linearly polarized. The angle of the refracted beam with respect to the normal is . . . . . . . $(\tan ^{-1}(1.52)=57.7^{\circ}$, refractive indices of air and glass are $1.00$ and $1.52$, respectively) (in $^{\circ}$)

The polarising angle for a transparent medium is $\theta$,and $v$ is the speed of light in that medium. Then the relation between $\theta$ and $v$ is (where $c$ is the velocity of light in air).

Select the correct statement.

$A$ ray of unpolarised light is incident on a glass surface of refractive index $1.73$ at the polarizing angle. The angle of refraction will be. [Take $\tan 60^{\circ} = 1.73$] (in $^{\circ}$)

$A$ beam of light both reflects and refracts at the surface between air and glass. The refractive index of the glass is $1.4$. If the refracted and the reflected rays are perpendicular to each other,then the angle of incidence in the air is