You are given prisms made of crown glass and flint glass with a wide variety of anlges. Suggest a combination of prisms will
b) disperse (and displace) a pencil of white light without much deviation.

Explanation

ii) For almost no devation
`(mu_(Lambda)-1)A+(mu'_(y)-1)A'=0`
Taking crown glass prism of certain angle, we go on - increasing angle of flint glass prism till this condition is met. In the final combination however, angle of flint glass prism will be smaller than the angle of crown glass prism as `mu'_(y)` for flint glass is more than `mu_(y)` for flint glass is more that `mu_(y)` for crown glass.