NTA Abhyas JEE Main2020PhysicsWave OpticsPractice
A ray of light passes four transparent glass slabs having refractive indices μ 1 , μ 2 , μ 3 and μ 4 as shown in the figure. If the emergent ray C D is parallel to the incident ray A B , then
Options
- Aμ 1 = μ 2
- Bμ 2 = μ 3
- Cμ 3 = μ 4
- Dμ 4 = μ 1
Correct answer
D. μ 4 = μ 1
Step-by-step solution
Applying Snell's law at B and C, μ sin i = constant or μ 1 sini B = μ 4 sub i c But since A B | | C D ∴ i B = i C or μ 1 = μ 4 The Snell's law, which the students read in their plus two syllabus μ = sin i sin r comes from μ sin i = constant μ 1 = μ 1 sini 1 = μ 2 sini 2 μ 2 = μ or sini = μ sinr or μ = sin i sin r