JEE Main 2022 · PhysicsMultiple choiceSingle correctMediumCalculation

JEE Main 28 July 2022, Shift 2, Physics Q16

Question 16 of 90 in this shift, Physics question 16 of 30, Section A.

The power of a lens (biconvex) is

1.25\ \mathrm{m^{-1}}

in particular medium. Refractive index of the lens is 1.5 and radii of curvature are 20 cm and 40 cm respectively. The refractive index of surrounding medium:

(1)1.0
(2) $\frac{9}{7}$ Official answer
(3) $\frac{3}{2}$
(4) $\frac{4}{3}$

Official answer

Option 2

NTA final key.

Chapter: Ray Optics and Optical Instruments
Topic: Lens Maker's Formula
Idea tested: Lens Immersed in a Liquid

Same idea in other shifts

Asked 6× in all

7 Apr 2025, Shift 1 · Q42A lens having refractive index 1.6 has focal length of 12 cm, when it is in air. Find the focal length of the lens when it is placed in…EasySingle correct
8 Apr 2025, Shift 2 · Q41A concave-convex lens of refractive index 1.5 and the radii of curvature of its surfaces are 30 cm and 20 cm, respectively. The concave…HardSingle correct
29 Jan 2024, Shift 1 · Q45A biconvex lens of refractive index 1.5 has a focal length of 20 cm in air. Its focal length when immersed in a liquid of refractive index…MediumSingle correct
11 Apr 2023, Shift 1 · Q52The radius of curvature of each surface of a convex lens having refractive index 1.8 is 20 cm. The lens is now immersed in a liquid of…MediumNumerical value
16 Mar 2021, Shift 2 · Q3The refractive index of a converging lens is 1.4. What will be the focal length of this lens if it is placed in a medium of same…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 108 of the 174 JEE Main shifts held from 2017 to 2026.