A thin prism of angle `15^(@)` made of glass of refractive index `mu_(1)=1.5` is combined with another prism of glass of refractive index `mu_(2)=1.75`. The combination of the prism produces dispersion without deviation. The angle of the second prism should be

Options

A. `12^(@)`
B. `5^(@)`
C. `7^(@)`
D. `10^(@)`

Answer

D

Explanation

Since, deviation is zero
`(n_(1) - 1) A_(1) - (n_(2) - 1) A_(2) = 0 `
`rArr " " A_(2) (1.75 - 1) = (1.5 - 1 )xx 15^(@)`
`A_(2) = (0.5 )/(0.75) xx 15^(@) = 10^(@).`