Optics Question 829
Question: Two beams of red and violet colors are made to pass separately through a prism (angle of the prism is $ 60{}^\circ $ ). In the position of minimum deviation, the angle of refraction will be
Options:
A) $ 30{}^\circ $ for both the colors
B) greater for the violet color
C) greater for the red color
D) equal but not $ 30{}^\circ $ for both the colors.
Show Answer
Answer:
Correct Answer: A
Solution:
[a] For minimum deviation the ray in the prism is parallel to the base of the prism. This condition does not depend on the color (or wave length) of incident radiation. So in both the cases, by geometry, $ r=30{}^\circ . $ So [a] is correct option.
