A thin prism `P_(1)` with angle `4degree` and made from glass of refractive index 1.54 is combined with another thin prism `P_(2)` made from glass of refractive index 1.72 to produce dispersion without deviation. The angle of the prism `P_(2)` is

Options

A. `2.6^(@)`
B. `3^(@)`
C. `4^(@)`
D. `5.33^(@)`

Answer

B

Explanation

For dispersion without deviation `(A)/(A^('))=((mu^(')-1))/((mu-1))`
`(4)/(A_(F))=((1.72))/((1.54))=(0.72)/(0.54)` or `A_(F)=(4xx0.54)/(0.72)=3^(@)`