The signals for the communication are passed through an optical fibre cable by the phenomenon called of light. (total internal reflection/ total internal refraction)

The diagram below shows a light source P embedded in a rectangular glass block ABCD of critical angle 42°. Complete the path of the ray PQ till it emerges out of the block. Write necessary angles.
 

For a right angled prism ray $1$is the incident ray and ray $2$ is the emergent ray, as shown in the figure. The refractive index of the prism is ____.

Three rays of light, namely red $\left(R\right)$, green $\left(G\right)$ and blue $\left(B\right)$ are incident on the face $PQ$ of a right angled prism $PQR$ as shown in figure.

The refractive indices of the material of the prism for red, green and blue wavelength are $1.27,1.42$ and $1.49$ respectively. The colour of the ray(s) emerging out of the face $PR$ is :

Show, by a ray-diagram, how a totally reflecting glass prism can be used to deviate a ray through $90°$.

In the given figure, the principal section of a glass prism is an isosceles triangle$\mathrm{ABC}$ with $AB=AC$ . The face $AC$ is silvered. A ray incident normally on face $AB\text{,}$ after two reflections emerges from the base$\mathrm{BC}$ in a direction perpendicular to it. What is the angle$\angle BAC$ of a prism?

Draw ray diagram to deviate a ray of light by $90°$, $180°$ and inversion without deviation. Name the phenomenon used and write its conditions.

Show, by ray-diagram, how a totally reflecting glass prism can be used to deviate a ray through $180°$.

A beam of light consisting of red, green and blue colours is incident on a right-angled prism. The refractive index of the material of the prism for the red, green and blue colours are $1.39, 1.44 \mathrm{and} 1.47$, respectively.

The prism will :-

Show, with the help of ray diagrams, how an image is produced in a totally-reflecting prism.

Two isosceles right angled prism are arranged as shown in the figure. Copy the diagram and complete the path of the ray AB along which it passes through the prisms and comes out. Name the phenomenon being displayed by the path of the ray in the given diagram.