Question

Briefly, describe an experiment to show that a prism itself produces no colour.

Answer 1

A prism itself produces no colour. This can be demonstrated by the following experiment.

Experiment: In figure below, white light from a slit s is made to pass through a prism P which forms the spectrum VR on a while screen AB. A narrow slit H is made on the screen AB parallel to the slit S to allow the light of a particular colour to pass through it. This light of  a particular colour is made to fall on a seconf prism Q placed with its base in opposite directionj to that of the prism P. The light after passing through the second prism Q is recieved on another white screen M.

It is observed that the colour of light onbtained on the screen M is sames as that of the light incident on the second prism Q through the slit H. If green light is incident on the prism Q, the screen M has only green colour. This proves that the prism itself produces no coours.