JEE Main 2017PhysicsRay OpticsMediumMCQ

JEE Main 2017 — Ray Optics Question with Solution

JEE Main 2017 (09 Apr Online)

Question

In an experiment a convex lens of focal length 15 cm is placed coaxially on an optical bench in front of a convex mirror at a distance of 5 cm from it. It is found that an object and its image coincide, if the object is placed at a distance of 20 cm from the lens. The focal length of the convex mirror is-

Choose an option

Show full solutionCorrect option: D
Correct answer
D27.5 cm

Step-by-step explanation



  Image by Lens -

-1-20+1v=1+15

V=+60

Distance of Image from mirror =60-5=55 cm

Path retraces when that image in at center of curvature of the mirror. Hence

R=55 cm

fmirror=R2=27.5 cm

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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.