The ray diagram for a prism whose one surface is reflecting is as shown. The value of $\theta$ will be

 

A light ray is incident perpendicularly to one face of a right angled prism and is totally internally reflected at the glass-air interface. If the angle of reflection is 45°, we conclude that the refractive index $\mu$ is

A light ray from air is incident (as shown in figure) at one end of a glass fiber (refractive index, $\mu =1.5$), making an incidence angle of  ${60}^{\circ }$ on the lateral surface, so that it undergoes total internal reflection. How much time would it take to traverse the straight fiber of length $1 \mathrm{km}$?

In the figure shown, for an angle of incidence $45°$ at the top surface, what should be the minimum refractive index needed for total internal reflection at vertical face?

A ray of light is incident at an angle $i$ from denser to the rarer medium: The reflected and the refracted rays are mutually perpendicular. If the angle of reflection and the angle of refraction are $r$ and $r\text{'}$ respectively, then the critical angle will be 

A ray of light is incident at an angle of ${45}^{\circ }$ from air to a glass slab at point $A,$ the angle of incidence being ${45}^{\circ }$. The minimum value of the refractive index of the material of the slab so that TIR takes place at $B$ is