The dispersive powers of crown and flint glasses are `0.03` and `0.05` respectively. The refractive indices for yellow light for these glasses are `1.517` and `1.621` respectively. It is desired to form an achromatic combination of prism of crown and flint glasses which can produce a deviation of `1^@` in the yellow ray. Find the refracting angles of the two prisms needed.

Options

A. refracting angle of crown glass is `4.8^(@)` and that of flint glass is `2.4^(@)`
B. refracting angle of crown glass is `2.4^(@)` and that of flint glass is `4.8^(@)`
C. refacting angle of both the glasses is `4.8^(@)` each.
D. refacting angle of both the glasses is `2.4^(@)` each.

Answer

A