$A$ beam of light consists of red,green,and blue colors. It is incident on the $AB$ face of a right-angled prism as shown in the figure. The refractive indices for red,green,and blue colors are $1.39$,$1.44$,and $1.47$ respectively. What will a person see when looking at the $AC$ surface of the prism?

$A$ ray of light is incident at an angle $i$ from a denser to a rarer medium. The reflected and the refracted rays are mutually perpendicular. The angle of reflection is $r$ and the angle of refraction is $r'$. Then the critical angle $C$ will be:

Explain the use of optical fibre in the medical field.

The refractive indices of the material of the prism and the liquid are $1.56$ and $1.32$ respectively. Find the value of $\theta$ for total internal reflection at the interface.

Light enters at an angle of incidence $\alpha$ into a transparent rod of refractive index $n.$ For what value of the refractive index of the material of the rod will the light,once entered into it,not leave it through its lateral face,regardless of the value of the angle of incidence $\alpha$?

$A$ point source of light $S$ is placed at the bottom of a vessel containing a liquid of refractive index $\mu = 5/3$. $A$ person is viewing the source from above the surface. There is an opaque disc $D$ of radius $r = 1\, cm$ floating on the surface of the liquid. The centre of the disc lies vertically above the source $S$. The liquid from the vessel is gradually drained out through a tap. The maximum height $h$ of the liquid for which the source cannot be seen at all from above is: (in $, cm$)