From the figure shown,establish a relation between $\mu_1, \mu_2, \mu_3$.

$A$ ray of light is incident at an angle $i$ on a glass slab of refractive index $\mu$. The angle between the reflected and refracted light is $90^{\circ}$. Then, the relationship between $i$ and $\mu$ is

$A$ ray of light passes through four transparent media with refractive indices $\mu_1, \mu_2, \mu_3$ and $\mu_4$ as shown in the figure. The surfaces of all media are parallel. If the emergent ray $CD$ is parallel to the incident ray $AB$,we must have

Shown in the figure is a transparent tank of length $30 \,cm$. $A$ black strip of width $3.8 \,cm$ is stuck on its left wall. When a source of light is kept to the left of it,a shadow of width $7.6 \,cm$ is formed on the right wall. Now,the tank is filled with a liquid of refractive index $n$,and the width of the shadow reduces to $6.4 \,cm$. The value of $n$ is closest to

What are optically denser and optically rarer media?

$A$ beam of light propagating in medium $A$ with index of refraction $n(A)$ passes across an interface into medium $B$ with index of refraction $n(B)$. The angle of incidence is greater than the angle of refraction; $v(A)$ and $v(B)$ denote the speed of light in $A$ and $B$. Then which of the following is true?