JEE Main 2022 · PhysicsNumerical answerNumerical valueMediumMulti-step

JEE Main 24 June 2022, Shift 1, Physics Q52

Question 52 of 90 in this shift, Physics question 22 of 30, Section B.

Two identical thin biconvex lenses of focal length 15 cm and refractive index 1.5 are in contact with each other. The space between the lenses is filled with a liquid of refractive index 1.25. The focal length of the combination is ______ cm.

Official answer

NTA final key (2022 Session 1).

Chapter: Ray Optics and Optical Instruments
Topic: Lens Maker's Formula
Idea tested: Lenses in Contact

Same idea in other shifts

Asked 3× in all

5 Apr 2026, Shift 2 · Q40A thin convex lens and a thin concave lens are kept in contact and are co-axial. Which of the following statements is correct for this…EasySingle correct
8 Apr 2025, Shift 2 · Q43A convex lens of focal length 30 cm is placed in contact with a concave lens of focal length 20 cm. An object is placed at 20 cm to the…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 42 of the 174 JEE Main shifts held from 2017 to 2026.