Question

An achromatic prism is made by combining two prisms `P_1(mu_v=1.523, mu_r=1.515)` and `P_2(mu_v=1.666, mu_r=1.650)`, where `mu` represents the refractive index. If the angle of the prism `P_1` is `10^@`, then the angle of prism `P_2` will be
A. `5^@`
B. `7.8^@`
C. `10.6^@`
D. `20^@`

Answer 1

Correct Answer - B
`mu=(1.523+1.515)/(2)=1.519`
`mu_2=(1.666+1.650)/(2)=1.658`
`(mu_1-1)A_1=(mu_2-1)A_2`
`(1.519-1)(10^@)=(1.658-1)A_2`
`A_2=7.8^@`