For a given medium, the polarizing angle is $60^o$. What will be the critical angle for this medium?

$A$ person lives in a high-rise building at a height of $30 \ m$ on the bank of a river. Across the river is a well-lit tower of height $60 \ m$. When the person looks through a polarizer at an appropriate angle at light from the top of the tower reflecting from the river surface,he finds the intensity of light is least. If the refractive index of water is $\frac{4}{3}$,the width of the river is ...... $m$.

$A$ beam of light $AO$ is incident on a glass slab $(\mu = 1.54)$ in a direction as shown in the figure. The reflected ray $OB$ is passed through a Nicol prism. On viewing through the rotating Nicol prism,we find that $(\tan 57^{\circ} = 1.54)$.

Light,whose electric field vectors are completely removed in the plane of incidence by using a good Polaroid,is incident on the surface of a prism at Brewster's angle. Choose the most suitable option for the phenomenon related to the prism.

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).

The refractive index of a medium is $\sqrt{3}$. If unpolarised light is incident on it at the polarizing angle of the medium,then the angle of refraction is......$^o$