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Saturday, 31 October

JEE Main · Physics · Ray Optics and Optical Instruments

Lens Immersed in a Liquid

JEE Main asked Lens Immersed in a Liquid 6 times in 6 of the 108 shifts Lumi analysed, in 2021, 2022, 2023, 2024 and 2025. It belongs to Lens Maker's Formula, in Ray Optics and Optical Instruments (Physics). The longest wait between two years asking it was 1 year. In 2025 it came in more than one shift of the same year.

Updated 2026-10-24

Times asked
6
in 6 shifts
Years
5 of 8
First asked
2021
last in 2025
Pattern
Asked most years
across the analysed shifts

Questions on this idea a shift, by year

2017–2026. Asked in 2021, 2022, 2023, 2024 and 2025. Years differ in how many shifts Lumi analysed, so each year is scaled to one shift of 25 Physics questions.

00.150.30’170’200.03’210.03’220.07’230.05’240.25’250’26

Raw count: 2017: 0 in 1 shift · 2020: 0 in 12 shifts · 2021: 1 in 24 shifts · 2022: 1 in 24 shifts · 2023: 1 in 12 shifts · 2024: 1 in 18 shifts · 2025: 2 in 8 shifts · 2026: 0 in 9 shifts.

Shift by shift

Each square is one analysed shift, in date order. Open a filled one for that paper.

  • 20260 of 9
  • 20252 of 8
  • 20241 of 18
  • 20231 of 12
  • 20221 of 24
  • 20211 of 24
  • 20200 of 12
  • 20170 of 1

Asked in that shift More than once Not asked

How JEE Main framed it

Single correct is the usual form. Skill tested: calculation.

  • Focal length of lens in liquid
  • Focal length of lens with liquid filled surface

Difficulty

Easy 2Medium 3Hard 1

1 of the 6 questions had a numerical answer.

Every question

All 6 questions

From the official JEE Main shift papers, newest first. Open one for the full question, the options and the official answer.

  1. 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
  2. 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
  3. 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
  4. 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
  5. 28 Jul 2022, Shift 2 · Q16The power of a lens (biconvex) is 1.25 m−11.25\ \mathrm{m^{-1}} in particular medium. Refractive index of the lens is 1.5 and radii of curvature…MediumSingle correct
  6. 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

Shifts: 16 Mar 2021, Shift 2, 28 Jul 2022, Shift 2, 11 Apr 2023, Shift 1, 29 Jan 2024, Shift 1, 7 Apr 2025, Shift 1, 8 Apr 2025, Shift 2.

Same topic

Other ideas in Lens Maker's Formula

Lens Maker's Formula has 16 ideas JEE Main has asked; 9 of them came up in more than one question. The 12 most asked are below.

Topic analysisChapter analysisStudy this chapterAll repeated ideas