If $n_{21} > 1$,then write the relation between the angle of incidence and the angle of refraction.

When light is refracted into a denser medium,

$A$ light ray is incident on a glass slab at an angle of incidence of $60^o$. If the angle between the reflected ray and the refracted ray is $90^o$,what is the refractive index of the glass slab?

$A$ light ray of frequency '$v$' and wavelength '$\lambda$' enters a liquid of refractive index $\frac{3}{2}$. The ray travels in the liquid with:

$A$ concave mirror is placed on a horizontal surface and two thin uniform layers of different transparent liquids (which do not mix or interact) are formed on the reflecting surface. The refractive indices of the upper and lower liquids are $\mu_1$ and $\mu_2$ respectively. The bright point source at a height $d$ ($d$ is very large in comparison to the thickness of the film) above the mirror coincides with its own final image. The radius of curvature of the reflecting surface is

$A$ ray of light travelling through glass of refractive index $\sqrt{2}$ is incident on a glass-air boundary at an angle of incidence of $45^{\circ}$. If the refractive index of air is $1$,then the angle of refraction will be: $[\sin 45^{\circ} = \frac{1}{\sqrt{2}}, \sin 90^{\circ} = 1]$ (in $^{\circ}$)