Question

Why does a light ray incident on a rectangular glass slab immersed in any medium emerges parallel to itself? Explain using a diagram.

Answer 1

Refraction of light:

1. The ray of light bends towards normal when moving from a rarer to a denser medium, and away from normal when moving from a denser to a rarer medium is known as refraction of light.

Explanation:

1. A glass slab's opposite faces are parallel. As a result, the first interface's angle of refraction becomes the second interface's angle of incidence, $\angle {\mathrm{r}}_1=\angle {\mathrm{r}}_2$.
2. The emerging ray bends to the point where, $\angle \mathrm{i}=\angle \mathrm{e}$.
3. According to the reversibility principle. As a result, the incident and emerging rays are aligned.