$A$ ray of light strikes a glass plate at an angle of $60^{\circ}$. If the reflected and refracted rays are perpendicular to each other,the refractive index of glass is

When unpolarized light is incident from air onto glass $(\mu = 1.5)$,then:

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

Unpolarised red light is incident on the surface of a lake at an incident angle $\theta_{R}$. An observer seeing the light reflected from the water surface through a polariser notices that on rotating the polariser,the intensity of light drops to zero at a certain orientation. The red light is replaced by unpolarised blue light. The observer sees the same effect with reflected blue light at an incident angle $\theta_{B}$. Then,

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: