JEE Main 2020PhysicsRay OpticsEasyMCQ

JEE Main 2020 — Ray Optics Question with Solution

JEE Main 2020 (05 Sep Shift 1)

Question

For a concave lens of focal length f, the relation between object and image distance u and v, respectively, from its pole can best be represented by (u=v is the reference line):

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Show full solutionCorrect option: A
Correct answer
A

Step-by-step explanation

From the lens formula, 1v-1u=1f

⇒v=f-f2u+f

 now, if we plot a graph between u and v 

When u→∞; v=f-f2∞=f

and for u→0; v=0

Given that u=v is a reference line, therefore, dvdu=0+f2u+f2

dvduu=0=0+f20+f2=1

The equation of tangent of the curve at the origin, v-0=1u-0⇒v=u

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About this question

This is a previous-year question from JEE Main 2020, 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.