Question

The refractive index of glass is 1.520 for red light and 1.525 for blue light. Let $ \quad D_{1}$ and $ \quad D_{2}$ be angles of minimum deviation for red and blue light respectively in a prism of this glass, then,:

• A. $ \quad D_{1} <\,D_{2}$
• B. $ \quad D_{1}=D_{2}$
• C. $ \quad D_{1}$ can be less than or greater than $ \quad D_{2}$ depending upon the angle of prism
• D. $ \quad D_{1} >D_{2}$

Answer 1

Answer: (A)

$ \quad D=\left(\mu-1\right)A$
For blue light $ \quad\mu$ is greater than that for red light,
$ so\, D_{2} >D_{1}\cdot$