(a) State the colour seen (i) at X

In the figure given alongside, a narrow beam of white light is shown to pass through a triangular glass prism. After passing through the prism, it produces a spectrum YX on the screen.(a) State the colour seen (i) at X

(a) (i) The colour seen at X is violet (since it shows the maximum deviation).

     (ii) The colour seen at Y is red (since it shows the least deviation).

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



The phenomenon of splitting white light into its components colours (violet, indigo, blue, green, yellow, orange and red) while passing through a prism is known as the Dispersion of light. In the spectrum, red is seen at the top as it has the longest wavelength whereas violet is seen at the bottom of the spectrum as it has the shortest wavelength.

The cause of the dispersion of light through the prism is because white light is a mixture of seven different colours and they get refracted (bend) at different angles in the prism medium due to differences in their speed and wavelengths. So they get separated.


Simply Easy Learning

Updated on: 10-Oct-2022


Kickstart Your Career

Get certified by completing the course

Get Started