How do you prove that a prism does not produce colours itself?

1.	How do you prove that a prism does not produce colours itself?
Answer» 1. A white light from a slit ‘S’ is made to pass through prism P which forms spectrum on a white screen AB. 2. A narrow slit H is made on the screen AB, parallel to slit S to allow the light of particular colour to pass through it. 3. The light of a particular colour is made to fall on the second prism Q placed with its base in opposite direction to that of the prism P. 4. The light after passing through the second prism Q is received on another white screen M. 5. It is observed that the colour of light obtained on the screen M is same as that of the light incident on the second prism Q through the slit H.

Answer»

1. A white light from a slit ‘S’ is made to pass through prism P which forms spectrum on a white screen AB.

2. A narrow slit H is made on the screen AB, parallel to slit S to allow the light of particular colour to pass through it.

3. The light of a particular colour is made to fall on the second prism Q placed with its base in opposite direction to that of the prism P.

4. The light after passing through the second prism Q is received on another white screen M.

5. It is observed that the colour of light obtained on the screen M is same as that of the light incident on the second prism Q through the slit H.

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