At what angle of incidence $i$ will the light reflected from water be completely plane-polarized (in $^\circ$)? (Given refractive index of water $\mu = 1.33$)

Unpolarised light is incident on the boundary between two dielectric media,whose dielectric constants are $2.8$ (medium $1$) and $6.8$ (medium $2$),respectively. To satisfy the condition that the reflected and refracted rays are perpendicular to each other,the angle of incidence should be $\tan ^{-1}\left(1+\frac{10}{\theta}\right)^{\frac{1}{2}}$. The value of $\theta$ is $.............$ (Given for dielectric media,$\mu_{r}=1$)

When an unpolarised light beam is incident from air onto glass $(n = 1.5)$ at the polarising angle:

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......$^o$

The critical angle of a certain medium is $\sin^{-1}\left(\frac{3}{5}\right)$. The polarizing angle of the medium is

For a given medium,the polarizing angle is $60^{\circ}$. The critical angle for this medium is . . . . . .