A thin prism P with angle `4^(@)` and made from glass of refractive index 1.54 is combined with another thin prism P made from glass of refractive index 1.72 to produce dispersion without deviation The angle of prism P is

Options

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

Answer

D

Explanation

Given angle of prism `P_(1)=4^(@)`
`P_(2)=?eta_(1)=1.54, eta_(2)=1.72`
Angle of deviation `delta=(n-1)A`
Dispesion produced by both the prism will be equal
Hence the angle of prism `P_(2) is =3^(@)`