Question

Two beams of red and violet colours are made to pass separately through a prism of $A = 60^\circ$. In the minimum deviation position, the angle of refraction inside the prism will be

• A. greater for violet colour
• B. $30^\circ$ for both the colours
• C. greater for red colour
• D. equal but not $30^\circ$ for both the colours

Answer 1

Answer: (B)

$30^\circ$ for both the colours

Answer 2

Here, Angle of prism, $A=60^{\circ}$ For minimum deviation, $A=2 r$ or $r=\frac{A}{2}=\frac{60^{\circ}}{2}=30^{\circ}$ for both colours.