JEE Main 2020PhysicsRay OpticsHardNumerical

JEE Main 2020 — Ray Optics Question with Solution

JEE Main 2020 (04 Sep Shift 1)

Question

In a compound microscope, the magnified virtual image is formed at a distance of 25 cm from the eye-piece. The focal length of its objective lens is 1 cm. If the magnification is 100 and the tube length of the microscope is 20 cm, then the focal length of the eye-piece lens (in cm) is ______

Enter your answer

Show full solutionCorrect answer: 6.25
Correct answer
6.25

Step-by-step explanation

M=v0u01+Dfe

M=Lf01+Dfe

100=2011+25fe ; 5=1+25fe

4=25fe ; fe=254=6.25 cm

Practice this on the real CBT interface

Solve this JEE Main question (and the rest of the Ray Optics chapter) on PrepSharp's TCS iON-style CBT player — with timer, bookmarks and session analytics.

Solve interactively →

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.