Two beams of red and violet colours are made to pass separately through a prism (angle of the prism is 60°). In the position of minimum deviation, the angle of refraction will be [2008]

Question

Two beams of red and violet colours are made to pass separately through a prism (angle of the prism is 60°). In the position of minimum deviation, the angle of refraction will be [2008]

Smart Achievers · Accepted Answer

(1)

For minimum deviation, the ray in the prism is parallel to the base of the prism. This condition does not depend on the colour (or wavelength) of incident radiation. Therefore, in both the cases, for both the colours by geometry, angle of refraction is r = 30°.

Solution

Q.
Two beams of red and violet colours are made to pass separately through a prism (angle of the prism is 60°). In the position of minimum deviation, the angle of refraction will be [2008]

1 30° for both the colours

2 Greater for the violet colour

3 Greater for the red colour

4 Equal but not 30° for both the colours

Ans.
(1)

For minimum deviation, the ray in the prism is parallel to the base of the prism. This condition does not depend on the colour (or wavelength) of incident radiation. Therefore, in both the cases, for both the colours by geometry, angle of refraction is r = 30°.

Want Us to Email you About Special Offers & Updates?