Question

A thin prism $P_1$ with angle $4^o$ 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

• A. ${5.33}^o$
• B. $4^o$
• C. $3^o$
• D. ${2.6}^o$

Answer 1

The correct option is C $3^o$

as there is no net deviation then ,

$A_1({\mu }_1-1)=A_2({\mu }_2-1)$

$4\times 0.54=A_2\times 0.72$

$A_2=3$

option $C$ is correct