Question

In the figure given below, a narrow beam of white light is shown to pass through a triangular glass prism. After passing through the prism, it produces a spectrum XY on the screen.

(i) Name the phenomenon. 

(ii) State the colours seen at X and Y. 

(iii)Why do different colours of white light bend at different angles through a prism?

Answer 1

(i) The phenomenon is called dispersion. 

(ii) X — Violet Y — Red 

(iii) Different colours of white light bend through different angles with respect to the incident beam of light due to difference in speed of light of different wavelengths.