JEE Main 2019 — Wave Optics Question with Solution
From: JEE Main 2019 (Online) 9th January Morning Slot
Question
Consider a tank made of glass(refractive index 1.5) with a thick bottom. It is filled with a liquid of refractive index . A student finds that, irrespective of what the incident angle i (see figure) is for a beam of light entering the liquid, the light reflected from the liquid glass interface is never completely polarized. For this to happen, the minimum value of is :
This question includes a diagram. The text above accompanies the figure.
Choose an option
Show full solutionCorrect option: B
Correct answer
B
Step-by-step explanation
When light is incident on the liquid at 90o, then from ssnells law,
1.sin90o = sin
sin = . . . . . . (1)
Between liquid and glass,
sin = 1.5 sin r
sin = 1.5 sin (90o )
tan = 1.5
tan =
sin = . . . . . . (2)
From (1) and (2) we get,
=
2 + (1.5)2 = 2 (1.5)2
=
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This is a previous-year question from JEE Main 2019, covering the Wave 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.