Question

A thin prism $P_1$ with angle $4^{\circ }$ and made from glass of refractive index 1.54 is combined with another prism $P_2$Made of glass of refractive index 1.72 to produce dispersion without deviation. The angle of prism $P_2$ is

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

Answer 1

The correct option is C $3^{\circ }$

Dispersion without deviation.
$({\mu }_1-1)A_1=({\mu }_2-1)A_2(1.54-1)4^{\circ }=(1.72-1)A_2\frac{54\times 4^{\circ }}{72}=A_2{A}_2=\frac{6}{2}=3^{\circ }$