Question

Explain lateral displacement in a glass slab ?
When a white light passes through a prism it disperses into seven colours but when d same white light passes through glass slab no dispersion takes place. Why

Answer 1

Lateral displacement:
The perpendicular displacement in the path of the incident ray as it emerges out from the denser medium, is called lateral displacement. It is calculated as the perpendicular distance between the incident ray and the emergent ray, which are parallel to each other.
The phenomenon of dispersion occurs in the case of prism. The light strikes on one surface of the prism undergoes refraction and passes through the glass of the prism, and when emerges out, it refracts again. This causes the dispersion of the light and splits the light into its constituent colours. The degree of bending depends on the angle at which the ray of light enters and leaves the faces of the prism. The faces of the prism are not parallel to each other.
For a glass slab, the opposite faces of the slab are parallel. So, no dispersion takes place and only a slight deviation occurs.