JEE Main · Physics · Ray Optics and Optical Instruments

Plano-Convex Lens Focal Length

JEE Main asked Plano-Convex Lens Focal Length 3 times in 3 of the 108 shifts Lumi analysed, in 2020 and 2021. 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 2020 it came in more than one shift of the same year.

Updated 2026-10-24

Times asked: 3; in 3 shifts
Years: 2 of 8
First asked: 2020; last in 2021
Pattern: Gone quiet; across the analysed shifts

Questions on this idea a shift, by year

2017–2026. Asked in 2020 and 2021. Years differ in how many shifts Lumi analysed, so each year is scaled to one shift of 25 Physics questions.

Raw count: 2017: 0 in 1 shift · 2020: 2 in 12 shifts · 2021: 1 in 24 shifts · 2022: 0 in 24 shifts · 2023: 0 in 12 shifts · 2024: 0 in 18 shifts · 2025: 0 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
20250 of 8
20240 of 18
20230 of 12
20220 of 24
20211 of 24
20202 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.

Radius of plano-convex lens from power ratio
Focal length of plano-convex lens

Difficulty

Easy 1Medium 2Hard 0

1 of the 3 questions had a numerical answer.

Every question

All 3 questions

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

Shifts: 8 Jan 2020, Shift 1, 6 Sep 2020, Shift 2, 17 Mar 2021, Shift 1.

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 analysis Chapter analysis Study this chapter All repeated ideas