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Saturday, 31 October

JEE Main 2020 · PhysicsNumerical answerNumerical valueHardMulti-step

JEE Main 4 September 2020, Shift 1, Physics Q24

Question 24 of 75 in this shift, Physics question 24 of 25.

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 __________.

Official answer

6.25

NTA final key (Sep 2020).

Chapter
Ray Optics and Optical Instruments
Topic
Optical Instruments
Idea tested
Compound Microscope Magnification

Same idea in other shifts

Asked 2× in all
  1. 3 Aug 2021, Shift 1 · Q17A compound microscope has a magnification of 30. Assuming that the final image is formed at the least distance of distinct vision (25…MediumSingle correct

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.