“A ray of light incident on a rectangular glass slab immersed in any medium emerges parallel to itself”. Draw labeled ray diagrams to justify the statement.

The ray after travelling in the medium, emerges from it at an angle of emergence ‘e’, which is equal to the angle of incidence and therefore, emerges parallel to the incident ray as shown in the figure. Had there been no medium, the light would have taken the path that is shown by the lighter line which is parallel to the emerging ray after travelling in the medium.

Note- Pictorial representation would be more helpful in understanding this concept, and it should be memorized that whenever light ray travels from a medium of low refractive index to a medium of higher refractive index, it bends towards the normal and vice versa when travels from a medium of higher refractive index to a medium of lower refractive index.