The critical angle for a monochromatic light going from medium $A$ to medium $B$ is $\theta$. If the speed of light in medium $A$ is $V$, then the speed of light in medium $B$ is

The refractive index of the medium is:

For a given pair of transparent media,the critical angle is maximum for which colour?

$A$ glass prism of refractive index $1.5$ is immersed in water (refractive index $\frac{4}{3}$) as shown in the figure. $A$ light beam incident normally on the face $AB$ is totally internally reflected at the face $AC$ to reach the face $BC$,if:

In the diagram shown,a ray of light is incident on the interface between medium $1$ and $2$ at an angle slightly greater than the critical angle. The light undergoes total internal reflection at this interface. After that,the light ray falls on the interface of medium $1$ and $3$,and again it undergoes total internal reflection. Which of the following relations should hold true?

It is found that electromagnetic signals sent inside a glass sphere from $A$ towards $B$ reach point $C$. The speed of electromagnetic signals in glass cannot be: