Spectrum – Notes

Dispersion and Recombination of White Light

The angle between the two refracting faces of a prism is called the angle of the prism or refracting angle ‘A’.

The angle between the incident ray and the emergent ray is called the angle of the deviation‘d’.

The angle of deviation depends on:

• The angle of incidence for A given colours is called dispersion.
• The angle of the prism
• The colour of the light incident on the prism
• The material of the prism

The splitting of white light into its constituent’s colours is called dispersion.

When white light passes through a prism, a band of seven colours obtained, which is called the spectrum.

A rainbow is a natural spectrum that occurs in the sky.