Learn

Saturday, 31 October

JEE Main · Physics · Dual Nature of Radiation and Matter

Two-Wavelength System of Equations

JEE Main asked Two-Wavelength System of Equations 7 times in 7 of the 108 shifts Lumi analysed, in 2020, 2021, 2023, 2024 and 2026. It belongs to Photoelectric Effect, in Dual Nature of Radiation and Matter (Physics). The longest wait between two years asking it was 2 years. In 2021 it came in more than one shift of the same year.

Updated 2026-10-24

Times asked
7
in 7 shifts
Years
5 of 8
First asked
2020
last in 2026
Pattern
Asked most years
across the analysed shifts

Questions on this idea a shift, by year

2017–2026. Asked in 2020, 2021, 2023, 2024 and 2026. Years differ in how many shifts Lumi analysed, so each year is scaled to one shift of 25 Physics questions.

00.10.20’170.08’200.10’210’220.07’230.05’240’250.11’26

Raw count: 2017: 0 in 1 shift · 2020: 1 in 12 shifts · 2021: 3 in 24 shifts · 2022: 0 in 24 shifts · 2023: 1 in 12 shifts · 2024: 1 in 18 shifts · 2025: 0 in 8 shifts · 2026: 1 in 9 shifts.

Shift by shift

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

  • 20261 of 9
  • 20250 of 8
  • 20241 of 18
  • 20231 of 12
  • 20220 of 24
  • 20213 of 24
  • 20201 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.

  • Threshold wavelength from two stopping potentials
  • Threshold wavelength from stopping potentials

Difficulty

Easy 0Medium 7Hard 0

Every question was multiple choice.

Every question

All 7 questions

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

  1. 2 Apr 2026, Shift 1 · Q42For a certain metal, when monochromatic light of wavelength λ\lambda is incident, the stopping potential for photoelectrons is 3Vo3V_o.…MediumSingle correct
  2. 31 Jan 2024, Shift 1 · Q46When a metal surface is illuminated by light of wavelength λ\lambda, the stopping potential is 8V. When the same surface is illuminated…MediumSingle correct
  3. 11 Apr 2023, Shift 1 · Q34A metallic surface is illuminated with radiation of wavelength λ\lambda, the stopping potential is V0V_0. If the same surface is…MediumSingle correct
  4. 25 Jul 2021, Shift 2 · Q18When radiation of wavelength λ\lambda is incident on a metallic surface, the stopping potential of ejected photoelectrons is 4.8 V. If…MediumSingle correct
  5. 25 Feb 2021, Shift 2 · Q13The stopping potential for electrons emitted from a photosensitive surface illuminated by light of wavelength 491 nm is 0.710 V. When the…MediumSingle correct
  6. 4 Aug 2021, Shift 2 · Q3Two wavelengths λ1=496 nm\lambda_1=496\,\mathrm{nm} and λ2=620 nm\lambda_2=620\,\mathrm{nm} fall on a metal surface. Calculate the work function if the…MediumSingle correct
  7. 3 Sep 2020, Shift 1 · Q18When the wavelength of radiation falling on a metal is changed from 500 nm to 200 nm, the maximum kinetic energy of the photoelectrons…MediumSingle correct

Shifts: 3 Sep 2020, Shift 1, 25 Feb 2021, Shift 2, 25 Jul 2021, Shift 2, 4 Aug 2021, Shift 2, 11 Apr 2023, Shift 1, 31 Jan 2024, Shift 1, 2 Apr 2026, Shift 1.

Same topic

Other ideas in Photoelectric Effect

Photoelectric Effect has 15 ideas JEE Main has asked; 13 of them came up in more than one question. The 12 most asked are below.

Topic analysisChapter analysisStudy this chapterAll repeated ideas