JEE MAIN - Physics (2006 - No. 14)
The refractive index of a glass is $$1.520$$ for red light and $$1.525$$ for blue light. Let $${D_1}$$ and $${D_2}$$ be angles of minimum deviation for red and blue light respectively in a prism of this glass. Then,
$${D_1} < {D_2}$$
$${D_1} = {D_2}$$
$${D_1}$$ can be less than or greater than $${D_2}$$ depending upon the angle of prism
$${D_1} > {D_2}$$
Paliwanag
For a thin prism, $$D = \left( {\mu - 1} \right)A$$
Since $${\lambda _b} < {\lambda _r} \Rightarrow {\mu _r} < {\mu _b} \Rightarrow {D_1} < {D_2}$$
Since $${\lambda _b} < {\lambda _r} \Rightarrow {\mu _r} < {\mu _b} \Rightarrow {D_1} < {D_2}$$