NeetVictoryQuestion 1: Composition and Size of the Nucleus
The number of neutrons in a nucleus of ²³⁸₉₂U is:
- A 330
- B 92
- C 146
- D 238
Answer: C. 146
Why: N = A − Z = 238 − 92 = 146.
NEET Physics: Nuclei. Chapter-wise Practice Questions and Test
Nuclei is a Class 12 Physics chapter that carries about 3.0% of the Physics questions in NEET. Practise it with 42 questions covering 4 topics, each with an explanation.
Practise Nuclei
Open in the appSets of 15 questions that adapt to your level, with an explanation for every answer.
Topics covered in Nuclei
- Composition and Size of the Nucleus (9 questions)
- Mass Defect and Binding Energy (11 questions)
- Nuclear Fission and Fusion (6 questions)
- Radioactivity and Decay Law (16 questions)
How often Nuclei has come up in NEET
Across the 13 previous year papers, Nuclei had 16 questions, about 1.2 a year. The most in one paper was 3, in NEET 2021.
| Paper | Questions from this chapter |
|---|---|
| NEET 2026 | 2 |
| NEET 2025 | 0 |
| NEET 2024 | 1 |
| NEET 2023 | 1 |
| NEET 2022 | 2 |
| NEET 2021 | 3 |
| NEET 2020 | 2 |
| NEET 2019 | 1 |
| NEET 2018 | 1 |
| NEET 2017 | 1 |
| NEET 2016 | 0 |
| Re-AIPMT 2015 | 0 |
| AIPMT 2014 | 2 |
Sample questions on Nuclei with answers
8 questions from the practice bank, spread across the chapter's topics. The full set is in the app.
Question 2: Mass Defect and Binding Energy
The binding energy per nucleon is greatest for nuclei of mass number about:
- A 12 (carbon) only
- B 238 (uranium)
- C 2 (deuterium)
- D 56 (iron)
Answer: D. 56 (iron)
Why: The curve peaks near A ≈ 56, so fusion of light nuclei and fission of heavy nuclei both release energy.
Question 3: Nuclear Fission and Fusion
Nuclear fusion requires very high temperatures because the nuclei:
- A must overcome their mutual Coulomb repulsion to come close enough for the nuclear force to act
- B are radioactive
- C must be ionised first only
- D are heavy and need to be melted
Answer: A. must overcome their mutual Coulomb repulsion to come close enough for the nuclear force to act
Why: Temperatures of 10⁷–10⁸ K give the necessary kinetic energy.
Question 4: Radioactivity and Decay Law
The half-life of a sample is 20 days. The fraction left undecayed after 60 days is:
- A 1/6
- B 1/9
- C 1/3
- D 1/8
Answer: D. 1/8
Why: 60 days is three half-lives: (1/2)³ = 1/8.
Question 5: Composition and Size of the Nucleus
The nuclear force is:
- A long-ranged and depends on charge
- B weaker than the electrostatic force at 1 fm
- C a gravitational force
- D short-ranged, strong, and independent of charge
Answer: D. short-ranged, strong, and independent of charge
Why: It acts mainly between nucleons that are within about 2–3 fm.
Question 6: Mass Defect and Binding Energy
The mass defect of a nucleus is 0.03 u. The energy equivalent is about (1 u = 931.5 MeV/c²):
- A 931 MeV
- B 0.03 MeV
- C 28 MeV
- D 2.8 MeV
Answer: C. 28 MeV
Why: E = 0.03 × 931.5 ≈ 27.9 MeV.
Question 7: Nuclear Fission and Fusion
The fusion of four hydrogen nuclei into one helium nucleus releases about:
- A 26.7 MeV
- B 200 MeV
- C 0.7 MeV
- D 931 MeV
Answer: A. 26.7 MeV
Why: This proton–proton cycle powers the Sun and other stars.
Question 8: Radioactivity and Decay Law
The activity of a radioactive sample is the:
- A energy released per decay
- B half-life of the sample
- C number of disintegrations per second, A = λN
- D number of atoms in it
Answer: C. number of disintegrations per second, A = λN
Why: Its SI unit is the becquerel (1 Bq = 1 decay per second); 1 curie = 3.7 × 10¹⁰ Bq.
Practise all of Nuclei
Open in the appFrequently asked questions
How many questions come from Nuclei in NEET?
Nuclei carries about 3.0% of the Physics questions in NEET. Across the 13 previous year papers on NeetVictory it appeared 16 times, about 1.2 questions a year.
Which class is Nuclei from?
Nuclei is a Class 12 Physics chapter in the NCERT syllabus.
Where can I practise Nuclei questions for NEET?
NeetVictory has 42 practice questions on Nuclei, each with an explanation, in sets of 15 that adapt to your level. This page shows a free sample.