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Friday, 9 October

JEE Main 2026 · PhysicsMultiple choiceSingle correctHardMulti-step

JEE Main 5 April 2026, Shift 1, Physics Q42

Question 42 of 75 in this shift, Physics question 17 of 25, Section A.

A compound microscope is designed with two symmetric biconvex lenses. The objective lens is cut vertically, creating two identical plano-convex lenses. One of them is used in place of original objective lens. To retain same magnification keeping the object distance unchanged, the tube length has to be
  1. (1)increased two timesOfficial answer
  2. (2)increased 32\frac{3}{2} times
  3. (3)decreased two times
  4. (4)decreased 32\frac{3}{2} times

Official answer

Option 1

NTA final key.

Chapter
Ray Optics and Optical Instruments
Topic
Optical Instruments
Idea tested
Microscope Tube Length

Same topic in other shifts

All Optical Instruments questions
  1. 4 Apr 2026, Shift 1 · Q44A telescope with objective diameter RR is used to observe a distant star emitting light of wavelength 500500 nm, at a resolution of…EasySingle correct
  2. 28 Jul 2022, Shift 1 · Q46In normal adjustment, for a refracting telescope, the distance between objective and eye piece is 30 cm. The focal length of the…EasySingle correct
  3. 3 Aug 2021, Shift 2 · Q15To view a small object with angular magnification 5, the power of the microscope needed is [The final image is formed at infinity]…EasySingle correct
  4. 3 Aug 2021, Shift 2 · Q16If a man having the least distance of distinct vision of 50 cm, what should be the focal length of the spectacles for the man ?EasySingle correct
  5. 18 Mar 2021, Shift 1 · Q16Your friend is having eye sight problem. She is not able to see clearly a distant uniform window mesh and it appears to her as non-uniform…MediumSingle correct
  6. 8 Jan 2020, Shift 1 · Q16The magnifying power of a telescope with tube length 60 cm is 5. What is the focal length of its eye piece ?EasySingle 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 42 of the 174 JEE Main shifts held from 2017 to 2026.