JEE Main 2017PhysicsRay OpticsHardMCQ

JEE Main 2017 — Ray Optics Question with Solution

JEE Main 2017 (08 Apr Online)

Question

Let the refractive index of a denser medium with respect to rarer medium be n12 and its critical angle be θC . At an angle of incidence A when light is travelling from denser medium to rarer medium, a part of the light is reflected and the rest is refracted and the angle between reflected and refracted rays is 90o. Angle A is given by 

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Show full solutionCorrect option: A
Correct answer
Atan-1⁡sin⁡θC

Step-by-step explanation



In accordance with Snell's law, μ=μRμD=sin⁡icsin⁡90o

here ic is the angle of incidence.

μRμD=sin⁡ic

μ=μRμD=sin⁡Asin⁡r

=sinAsin90°-A=sinAcosA

μRμD=tan⁡A.

The critical angle is related to the angle A as tan⁡A=sin⁡θC

A=tan-1⁡sin⁡θC.

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About this question

This is a previous-year question from JEE Main 2017, covering the Ray Optics chapter of Physics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.