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Saturday, 31 October

JEE Main · Physics · Nuclei

Activity and Rate of Decay

JEE Main asked Activity and Rate of Decay 3 times in 3 of the 108 shifts Lumi analysed, in 2021, 2022 and 2023. It belongs to Radioactive Decay, in Nuclei (Physics). The longest wait between two years asking it was 1 year.

Updated 2026-10-24

Times asked
3
in 3 shifts
Years
3 of 8
First asked
2021
last in 2023
Pattern
Comes in cycles
across the analysed shifts

Questions on this idea a shift, by year

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

00.050.10’170’200.03’210.03’220.07’230’240’250’26

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: 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
  • 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.

  • Activity of sample from half-life
  • Activity from decay constant and mass

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.

  1. 10 Apr 2023, Shift 1 · Q56The decay constant for a radioactive nuclide is 1.5×10−5 s−11.5\times10^{-5}\,s^{-1}. Atomic weight of the substance is 60 g mole−1^{-1}, (…EasyNumerical value
  2. 26 Jul 2022, Shift 1 · Q33The disintegration rate of a certain radioactive sample at any instant is 4250 disintegrations per minute. 10 minutes later, the rate…MediumSingle correct
  3. 16 Mar 2021, Shift 2 · Q12The half-life of Au198\mathrm{Au^{198}} is 2.7 days. The activity of 1.50 mg of Au198\mathrm{Au^{198}} if its atomic weight is 198 g…MediumSingle correct

Shifts: 16 Mar 2021, Shift 2, 26 Jul 2022, Shift 1, 10 Apr 2023, Shift 1.

Same topic

Other ideas in Radioactive Decay

Radioactive Decay has 12 ideas JEE Main has asked; 9 of them came up in more than one question.

Topic analysisChapter analysisStudy this chapterAll repeated ideas