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Sunday, 25 October

JEE Main · Physics · Class 12

Nuclei: JEE Main previous year questions

84 questions in 71 of the 108 JEE Main shifts Lumi analysed, asked in 8 of 8 years. Here is what this chapter tests and how.

Study this chapter
Questions
84
in 71 of 108 shifts · 8 of 8 years
Average a shift
0.7
of 25 Physics · 0.7 since 2024 0.0
Typical range
0.6–0.8
questions a shift; fewest 0.5, most 0.8
Weighted estimate
0.7
model, recent years count more · about 2.8 marks
  • Typical range (fact)
  • Average a shift (fact)
  • Weighted estimate (model)

Questions are counted per shift, out of the 25 each subject has, in the shifts Lumi analysed; papers that offered 30 a subject (2017, 2021–2024) are scaled to 25. Typical range: the middle six of the eight years (2017, 2020–2026), leaving out the single highest and lowest year. The average and the range are historical fact. The weighted estimate is a model: each year's share, with recent years counting more (half-life three years), and chapters NTA dropped from the syllabus set near zero. It is a guide to effort, not a forecast of the paper.

What to do

How to spend time on Nuclei

Priority

Should do

One of the 10 Physics chapters that took Physics from half to 80% of its questions in the 108 shifts analysed. How bands are set

Past questions
84in 71 of 108 shifts
Study plan gives it
11 hover 12 months; 8 h over 6
Study this chapter →

Ideas asked most often

  1. Nuclear Radius and Density10×
  2. Half-Life Calculations10×
  3. Integer Half-Life Shortcuts7×
  4. Binding Energy per Nucleon6×
  5. Mass Defect Calculation5×

120 of the 163 ideas in Lumi’s map of this chapter have not been asked or touched in the shifts analysed. Of its idea-tagged questions from 2024 on, 39% tested an idea not asked in an earlier year, so learn the whole chapter, not just the list above.

Within each subject, chapters in NTA's 2026 syllabus are ranked by their average questions a shift over all 8 years analysed (history, not the model). Going down that list, the chapters that together held the first half of the subject's questions are Must do; the next ones, up to 80%, are Should do; the rest are Lower priority.

Key findings

Nuclei at a glance

  1. 01

    61%

    of its 28 questions from 2024 on that Lumi matched to an idea tested one JEE Main had asked in an earlier year; 100% came from a topic asked in an earlier year.

  2. 02

    74%

    of the 163 ideas in Lumi's map of the chapter have not been asked or touched on in the shifts analysed.

  3. 03

    24%

    of its questions asked for a numerical answer, 0.8 times the Physics average.

  4. 04

    2%

    of its questions were rated hard, against 5% across all Physics questions in the same shifts.

Questions a shift, year by year

Out of the 25 Physics questions in a shift. Years differ in how many shifts Lumi analysed, so each year is scaled to one shift.

0240.8’170.5’200.6’210.7’220.8’230.8’240.6’250.7’26

Raw count: 2017: 1 in 1 shift · 2020: 6 in 12 shifts · 2021: 18 in 24 shifts · 2022: 20 in 24 shifts · 2023: 11 in 12 shifts · 2024: 17 in 18 shifts · 2025: 5 in 8 shifts · 2026: 6 in 9 shifts.

Kind of question

SHARE OF QUESTIONS
  • Calculation38%
  • Numerical answer24%
  • Conceptual10%
  • Multi-step7%
  • Application7%
  • Diagram based6%
  • Recall, single correct5%
  • Assertion–reason2%
  • Match the list1%

Most common asks: time interval between fractional decays (2); time for fractional decay (2); fusion energy from binding energy per nucleon (2).

Profile

This chapter in numbers

Where it ranks, how steady it is, and what it costs to study.

Rank, all JEE chapters
#58
of 70 by weighted estimate
Rank in Physics
#21
of 28 chapters
Share of Physics
2.8%
of its questions, all shifts analysed
Busiest year
2017
0.8 questions a shift
Year to year
Steady
varies by about 0.1 questions a shift
Long-run direction
-0.00
questions a shift, per year
Easy questions
58%
2% rated hard
Numerical answer
24%
0.8× the Physics rate
With a figure
6%
graph, diagram or structure
Study time
11 h
8 h on a 6-month plan
Marks per study hour
0.26
#12 of 70 chapters
Foundation for others
33%
of its ideas are used in other chapters

Difficulty, year by year

Each question rated easy, medium or hard. Each bar is that year’s split, so years compare directly; the number is the questions in that year’s analysed shifts (1 to 24 shifts a year).

  • 20171
  • 20206
  • 202118
  • 202220
  • 202311
  • 202417
  • 20255
  • 20266
  • Easy
  • Medium
  • Hard

What it asks you to do

SHARE OF QUESTIONS
  • Calculation57%
  • Conceptual14%
  • Multi-step11%
  • Application7%
  • Data or graph6%
  • Recall5%

Coverage

How much of the chapter JEE Main has used

We split the chapter into 163 ideas. In the 108 shifts analysed, JEE Main built a question around 30 of them. Most of the chapter has never been the main idea of a question, so past questions alone leave most of it out.

Asked as the main idea
30
Touched on in a question
13
Never asked
120

Topics

What repeats, topic by topic

This chapter's questions per topic in each year's analysed shifts. The number is the count; the shade is scaled to one shift, so a year with more analysed shifts (1 to 24 a year) does not look darker.

’17’20’21’22’23’24’25’26
016+questions in that year’s analysed shifts, shaded per shift
  • Radioactive Decay

    As a topic: 40 questions in 7 of 8 years, most often single correct, 18% numerical answer.

  • Nuclear Binding Energy

    As a topic: 35 questions in 7 of 8 years, most often single correct, 31% numerical answer.

  • Fission and Fusion

    As a topic: 9 questions in 3 of 8 years, most often single correct, 22% numerical answer.

Drill down

Topic, idea, question

Open a topic to see every idea JEE Main tested inside it, then open an idea to read the questions. Each row shows its 8 years.

  • Open40 · 48%216145

    12 ideas inside

    • OpenRepeated10 · 25%423
    • OpenRepeated7 · 18%25
    • OpenRepeated5 · 13%2
    • OpenRepeated3 · 8%
    • OpenRepeated3 · 8%2
    • OpenRepeated3 · 8%2
    • OpenRepeated2 · 5%
    • OpenRepeated2 · 5%
    • OpenRepeated2 · 5%
    • Open1 · 3%
    • Open1 · 3%
    • Open1 · 3%
  • Open35 · 42%32661035
  • Open9 · 11%7

Squares are the 8 years with analysed shifts, 2017 to 2026. A number is the questions that year when there is more than one; the shade is scaled to one shift, so a year with more analysed shifts (1 to 24 a year) does not look darker. Share is of the level above.

Ideas

The exact ideas JEE Main has asked

Inside the topics, 30 different ideas were tested; 19 came more than once. These are the repeats, then the ideas new since 2024.

Dots are the 8 years with analysed shifts, 2017 to 2026.

Every question

All 84 Nuclei questions

Newest first, shift by shift. The newest 40 show their opening words; older ones name the idea they tested. Each opens with its options and the official answer.

JEE Main 20266 questions

  1. 2 Apr 2026, Shift 2 · Q44The binding energy per nucleon of 20983Bi\frac{209}{83}Bi isMediumSingle correct
  2. 4 Apr 2026, Shift 1 · Q29Two nuclei of mass number 33 combine with another nucleus of mass number 44 to yield a nucleus of mass number 1010. If the binding…MediumSingle correct
  3. 5 Apr 2026, Shift 2 · Q44Assuming the experimental mass of 612C{}^{12}_{6}\mathrm{C} as 12 u, the mass defect of 612C{}^{12}_{6}\mathrm{C} atom is ________…EasySingle correct
  4. 6 Apr 2026, Shift 1 · Q48The energy released when 717.13\frac{7}{17.13} kg of 37Li^{7}_{3}\mathrm{Li} is converted into 24He^{4}_{2}\mathrm{He} by proton bombardment is…MediumNumerical value
  5. 6 Apr 2026, Shift 2 · Q41The energy released if hydrogen atoms are combined to form 24He^{4}_{2}\mathrm{He} is __________ MeV. (Take binding energies per nucleon of…EasySingle correct
  6. 8 Apr 2026, Shift 2 · Q44Two radioactive substances A and B of mass numbers 200 and 212 respectively, shows spontaneous α\alpha-decay with same QQ value of 1…MediumSingle correct

JEE Main 20255 questions

  1. 2 Apr 2025, Shift 2 · Q38Energy released when two deuterons (1H2_1\mathrm{H}^2) fuse to form a helium nucleus (2He4_2\mathrm{He}^4) is : (Given : Binding energy per…EasySingle correct
  2. 3 Apr 2025, Shift 1 · Q44Match the LIST-I with LIST-II LIST-I A.…MediumMatch the list
  3. 4 Apr 2025, Shift 2 · Q42A radioactive material P first decays into Q and then Q decays to non-radioactive material R. Which of the following figure represents…MediumDiagram basedHas a figure
  4. 7 Apr 2025, Shift 2 · Q44Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : The density of…EasyAssertion–reason
  5. 8 Apr 2025, Shift 2 · Q44For a nucleus of mass number A and radius R, the mass density of nucleus can be represented asEasySingle correct

JEE Main 202417 questions

  1. 4 Apr 2024, Shift 1 · Q47Which of the following nuclear fragments corresponding to nuclear fission between neutron (01n^{1}_{0}\mathrm{n}) and uranium isotope…EasySingle correct
  2. 4 Apr 2024, Shift 2 · Q51The disintegration energy QQ for the nuclear fission of 235U→140Ce+94Zr+n^{235}U \to {}^{140}Ce + {}^{94}Zr + n is ________ MeV. Given atomic masses of…MediumNumerical value
  3. 5 Apr 2024, Shift 1 · Q59If three helium nuclei combine to form a carbon nucleus then the energy released in this reaction is ________ ×10−2\times10^{-2} MeV. (Given…MediumNumerical value
  4. 8 Apr 2024, Shift 1 · Q46Binding energy of a certain nucleus is 18×10818\times10^8 J. How much is the difference between total mass of all the nucleons and nuclear…EasySingle correct
  5. 8 Apr 2024, Shift 2 · Q47If MoM_o is the mass of isotope 512B{}^{12}_{5}\mathrm{B}, MPM_P and MnM_n are the masses of proton and neutron, then nuclear binding energy…EasySingle correct
  6. 8 Apr 2024, Shift 2 · Q48In a hypothetical fission reaction 92X236→56Y141+36Z92+3R{}_{92}X^{236} \rightarrow {}_{56}Y^{141} + {}_{36}Z^{92} + 3\mathbf{R} The identity of emitted…EasySingle correct
  7. 9 Apr 2024, Shift 1 · Q47The energy equivalent of 11 g of substance is :EasySingle correct
  8. 9 Apr 2024, Shift 1 · Q60A star has 100%100\% helium composition. It starts to convert three 4He{}^4\mathrm{He} into one 12C{}^{12}\mathrm{C} via triple alpha process…HardNumerical value
  9. 9 Apr 2024, Shift 2 · Q37The energy released in the fusion of 2 kg2\ kg of hydrogen deep in the sun is EHE_H and the energy released in the fission of 2 kg2\ kg of…MediumSingle correct
  10. 1 Feb 2024, Shift 1 · Q60The radius of a nucleus of mass number 64 is 4.8 fermi. Then the mass number of another nucleus having radius of 4 fermi is…EasyNumerical value
  11. 1 Feb 2024, Shift 2 · Q47From the statements given below : (A) The angular momentum of an electron in nthn^{th} orbit is an integral multiple of ℏ\hbar. (B)…MediumOther
  12. 27 Jan 2024, Shift 1 · Q60In a nuclear fission process, a high mass nuclide (A ≈\approx 236) with binding energy 7.6 MeV/Nucleon dissociated into middle mass…EasyNumerical value
  13. 29 Jan 2024, Shift 1 · Q47The explosive in a Hydrogen bomb is a mixture of 1H2{}_1\mathrm{H}^2, 1H3{}_1\mathrm{H}^3 and 3Li6{}_3\mathrm{Li}^6 in some condensed form.…MediumSingle correct
  14. 30 Jan 2024, Shift 2 · Q47In a nuclear fission reaction of an isotope of mass MM, three similar daughter nuclei of same mass are formed. The speed of a daughter…MediumSingle correct
  15. 31 Jan 2024, Shift 1 · Q60The mass defect in a particular reaction is 0.4g. The amount of energy liberated is n×107n\times10^7 kWh, where n=n= _______. (speed of light…EasyNumerical value
  16. 31 Jan 2024, Shift 2 · Q47The mass number of nucleus having radius equal to half of the radius of nucleus with mass number 192 is:EasySingle correct
  17. 31 Jan 2024, Shift 2 · Q60A nucleus has mass number A1A_1 and volume V1V_1. Another nucleus has mass number A2A_2 and Volume V2V_2. If relation between mass number…EasyNumerical value

JEE Main 202311 questions

  1. 8 Apr 2023, Shift 1 · Q43For a nucleus ZAX{}^{A}_{Z}\mathrm{X} having mass number A and atomic number Z A. The surface energy per nucleon…MediumOther
  2. 8 Apr 2023, Shift 1 · Q55A nucleus with mass number 242242 and binding energy per nucleon as 7.6 MeV7.6\ \mathrm{MeV} breaks into two fragment each with mass number…EasyNumerical value
  3. 8 Apr 2023, Shift 2 · Q44A radio active material is reduced to 1/8 of its original amount in 3 days. If 8×10−38\times10^{-3} kg of the material is left after 5 days…MediumSingle correct
  4. 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
  5. 10 Apr 2023, Shift 2 · Q44The half life of a radioactive substance is T. The time taken, for disintegrating 78\frac{7}{8}th part of its original mass will be:EasySingle correct
  6. 11 Apr 2023, Shift 1 · Q33Two radioactive elements A and B initially have same number of atoms. The half life of A is same as the average life of B. If λA\lambda_A…EasySingle correct
  7. 11 Apr 2023, Shift 2 · Q55A nucleus disintegrates into two nuclear parts, in such a way that ratio of their nuclear sizes is 1:21/31 : 2^{1/3}. Their respective speed…MediumNumerical value
  8. 12 Apr 2023, Shift 1 · Q60A common example of alpha decay is 92238U⟶ 90234Th+2He4+Q^{238}_{92}\mathrm{U} \longrightarrow\, ^{234}_{90}\mathrm{Th} + {}_{2}\mathrm{He}^{4} + Q Given :…EasyNumerical value
  9. 13 Apr 2023, Shift 1 · Q4692238A→ 90234B+ 24D+Q^{238}_{92}A \rightarrow\, ^{234}_{90}B + \,^{4}_{2}D + Q In the given nuclear reaction, the approximate amount of energy released will…EasySingle correct
  10. 13 Apr 2023, Shift 2 · Q48Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R Assertion A : The binding energy per…MediumAssertion–reason
  11. 15 Apr 2023, Shift 1 · Q44The half-life of a radioactive nucleus is 5 years. The fraction of the original sample that would decay in 15 years is:EasySingle correct

JEE Main 202220 questions

  1. 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
  2. 26 Jul 2022, Shift 2 · Q49Nuclear Radius and Density · Easy · Single correct
  3. 26 Jul 2022, Shift 2 · Q54Binding Energy per Nucleon · Medium · Numerical value
  4. 27 Jul 2022, Shift 1 · Q48Integer Half-Life Shortcuts · Easy · Single correct
  5. 27 Jul 2022, Shift 2 · Q48Half-Life Calculations · Easy · Single correct
  6. 28 Jul 2022, Shift 1 · Q48Integer Half-Life Shortcuts · Easy · Single correct
  7. 28 Jul 2022, Shift 1 · Q52Integer Half-Life Shortcuts · Easy · Numerical value
  8. 28 Jul 2022, Shift 2 · Q18Integer Half-Life Shortcuts · Easy · Single correct
  9. 29 Jul 2022, Shift 2 · Q41Nuclear Radius and Density · Easy · Other
  10. 29 Jul 2022, Shift 2 · Q59Statistical Decay Law · Medium · Numerical value
  11. 24 Jun 2022, Shift 1 · Q45Q-Value Calculation · Easy · Single correct
  12. 24 Jun 2022, Shift 2 · Q56Integer Half-Life Shortcuts · Medium · Numerical value
  13. 25 Jun 2022, Shift 2 · Q47Nuclear Radius and Density · Easy · Diagram based · has a figure
  14. 26 Jun 2022, Shift 1 · Q48Counting Alpha and Beta Emissions · Easy · Single correct
  15. 26 Jun 2022, Shift 2 · Q48Parallel Decay Branching · Easy · Single correct
  16. 28 Jun 2022, Shift 1 · Q45Q-Value and Reaction Spontaneity · Medium · Single correct
  17. 28 Jun 2022, Shift 2 · Q48Statistical Decay Law · Medium · Other
  18. 29 Jun 2022, Shift 1 · Q33Half-Life Calculations · Easy · Single correct
  19. 29 Jun 2022, Shift 2 · Q35Counting Alpha and Beta Emissions · Easy · Single correct
  20. 29 Jun 2022, Shift 2 · Q58Fractional Remainder Shortcut · Easy · Numerical value

JEE Main 202118 questions

  1. 3 Aug 2021, Shift 2 · Q12Mass Defect Calculation · Easy · Single correct
  2. 3 Aug 2021, Shift 2 · Q18Half-Life Calculations · Easy · Single correct
  3. 3 Aug 2021, Shift 2 · Q25Half-Life Calculations · Easy · Numerical value
  4. 4 Aug 2021, Shift 1 · Q4Counting Alpha and Beta Emissions · Easy · Single correct
  5. 26 Aug 2021, Shift 2 · Q6Successive Decay Chains · Hard · Diagram based · has a figure
  6. 27 Aug 2021, Shift 1 · Q19Half-Life Calculations · Easy · Single correct
  7. 31 Aug 2021, Shift 1 · Q3Successive Decay Chains · Medium · Diagram based · has a figure
  8. 25 Feb 2021, Shift 1 · Q19Integer Half-Life Shortcuts · Medium · Single correct
  9. 26 Feb 2021, Shift 2 · Q1Mean Life Calculation · Easy · Single correct
  10. 22 Jul 2021, Shift 2 · Q19Alpha Decay Kinematics and Q-Value · Easy · Single correct
  11. 25 Jul 2021, Shift 1 · Q1Activity from Sample Mass · Medium · Single correct
  12. 25 Jul 2021, Shift 1 · Q5Statistical Decay Law · Medium · Single correct
  13. 25 Jul 2021, Shift 2 · Q27Integer Half-Life Shortcuts · Easy · Numerical value
  14. 25 Jul 2021, Shift 2 · Q28Total Binding Energy · Easy · Numerical value
  15. 16 Mar 2021, Shift 2 · Q10Half-Life Calculations · Easy · Single correct
  16. 16 Mar 2021, Shift 2 · Q12Activity and Rate of Decay · Medium · Single correct
  17. 18 Mar 2021, Shift 1 · Q11Parallel Decay Branching · Medium · Single correct
  18. 18 Mar 2021, Shift 2 · Q20Beta Decay Mechanisms · Medium · Single correct

JEE Main 20206 questions

  1. 2 Sep 2020, Shift 1 · Q18Reactor Power Calculation · Medium · Single correct
  2. 3 Sep 2020, Shift 1 · Q19Statistical Decay Law · Easy · Single correct
  3. 3 Sep 2020, Shift 2 · Q18Nuclear Radius and Density · Easy · Single correct
  4. 4 Sep 2020, Shift 2 · Q18Binding Energy per Nucleon · Easy · Single correct
  5. 5 Sep 2020, Shift 1 · Q18Half-Life Calculations · Medium · Diagram based · has a figure
  6. 6 Sep 2020, Shift 2 · Q18Q-Value and Reaction Spontaneity · Medium · Single correct

JEE Main 20171 question

  1. 2 Apr 2017 (offline) · Q26Statistical Decay Law · Medium · Single correct

Questions from the official JEE Main papers published by NTA. Chapter, topic and idea tags, counts and notes are Lumi’s. Pattern: Asked most years.

More Physics, Class 12

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