Question

A ray of light passes through four transparent media with refractive indices`mu_1`,`mu_2`,`mu_3` and `mu_4` as shown in the figure. The surfaces of all media are parallel. If the emergent ray CD is parallel to the incident ray AB, we must have

A. `mu_(1)=mu_(2)`
B. `mu_(2)=mu_(3)`
C. `mu_(3)=mu_(4)`
D. `mu_(4)=mu_(1)`

Answer 1

Correct Answer - D
For successive refraction through different media `mu sin theta=` constant. Here as `theta` is same in two extreme media `, mu_(1)=mu_(2)`