Question

After refraction through a rectangular glass slab the emergent ray is ___________.

Answer 1

Refraction through a rectangular glass slab

1. We will observe the relationship between the incident and emergent ray and the relationship between the incident and refracted angle with the help of the above diagram.
2. The angles $\mathrm{i},\mathrm{r}$ and $\mathrm{e}$ in the given figure stand for incidence, refraction, and emergence, respectively.
3. We know that the light bends toward the normal when it enters a denser medium from a rarer one, and the opposite is true, when it enters a rarer medium from a denser medium and the density of glass is greater than density of air.
4. So, the light rays are refracted when they enter a glass medium, where they bend in the direction of the typical light ray, this light, which has been refracted, now passes through the glass slab and exits it by refracting from the opposite interface boundary and, ray gets refracted and bends away from normal because it moves from a glass medium to air.
5. Since they are adjacent interior angles to two parallel lines or the normal, the angles $\mathrm{r}$ and $\mathrm{r}\text{'}$ are equivalent.
6. Since the emergent ray and incident ray are forming the same angle after and before refraction on the same medium, the angle of incidence and angle of emergence are therefore equal.

Hence, after refraction through a rectangular glass slab, the emergent ray is parallel to each other.