Question
Question: A ray of light passes through four transparent media with refractive indices \(\mu _ { 1 } \cdot \mu...
A ray of light passes through four transparent media with refractive indices μ1⋅μ2,μ3, and μ4 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
μ1=μ2
B
μ2=μ3
C
μ3=μ4
D
μ4=μ1
Answer
μ4=μ1
Explanation
Solution
For successive refraction through difference media μsinθ= constant.
Here as θ is same in the two extreme media. Hence μ1=μ4