Draw a ray diagram to explain the term angle of deviation. (ii) Why do the component colours of incident white light split into a spectrum

Question

(i) Draw a ray diagram to explain the term angle of deviation.
(ii) Why do the component colours of incident white light split into a spectrum while passing through a glass prism, explain.
(iii) Draw a labelled ray diagram to show the formation of a rainbow.

Answer 1

(i) Emergent ray bends at an angle to the direction of the incident ray and the angle between them is known as angle of deviation.

(ii) When a beam of light enters a prism, it gets refracted and splits into its seven constituent colours. This splitting of the light ray occurs because of the different angles of bending of each colour. Hence, each colour passing through the prism bends at different angles with the respect to the incident beam. This gives rise to the formation of the colour spectrum.