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,

Options

A. `D_(1) = D_(2)`
B. `D_(1) lt D_(2)`
C. `D_(1) gt D_(2)`
D. `D_(1)` can be greater than or less than `D_(2)` depending upon the refractive angle of the prism

Answer

B

Explanation

For a small angled prism , `delta = A( n-1)`
`therefore D_(1) = A (n_(g) - 1) and D_(2) = A(n_(B) - 1)`
But `n_(B) gt n_(R) therefore D_(2) gt D_(1) or D_(1) lt D_(2)`