Question

Answer the following question in detail.

What are the different types of dispersions of light? Why do they occur?

Answer 1

1. There are two types of dispersions:
   a. Angular dispersion
   b. Lateral dispersion
2. The refractive index of material depends on the frequency of incident light. Hence, for different colours, the refractive index of the material is different.
3. For an obliquely incident ray, the angles of refraction are different for each colour and they separate as they travel along different directions resulting in angular dispersion.
4. When a polychromatic beam of light is obliquely incident upon a plane parallel transparent slab, emergent beam consists of all component colours separated out.
5. In this case, these colours are parallel to each other and are also parallel to their initial direction resulting in lateral dispersion.