Learn

Saturday, 31 October

JEE Main · Physics · Ray Optics and Optical Instruments

Focal Length Relation

JEE Main asked Focal Length Relation once in the 108 shifts Lumi analysed, on 24 Feb 2021, Shift 1. It belongs to Spherical Mirrors, in Ray Optics and Optical Instruments (Physics).

Updated 2026-10-24

Times asked
1
in 1 shift
Years
1 of 8
First asked
2021
the only year
Pattern
Gone quiet
asked once so far

Questions on this idea a shift, by year

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

00.050.10’170’200.03’210’220’230’240’250’26

Raw count: 2017: 0 in 1 shift · 2020: 0 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
  • 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: recall.

  • Focal length and radius of curvature of mirror

Difficulty

Easy 1Medium 0Hard 0

The question was multiple choice.

Every question

The question

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

  1. 24 Feb 2021, Shift 1 · Q19The focal length ff is related to the radius of curvature r of the spherical convex mirror by :EasySingle correct

Shift: 24 Feb 2021, Shift 1.

Same topic

Other ideas in Spherical Mirrors

Spherical Mirrors has 12 ideas JEE Main has asked; 3 of them came up in more than one question.

Topic analysisChapter analysisStudy this chapterAll repeated ideas