Class 12 Physics Chapter 13, Nuclei, covers nuclear structure, binding energy, and radioactive decay. The chapter carries 3 marks in CBSE and appears in JEE Main and NEET every year. This page hosts the Nuclei Formula Sheet PDF with all 9 core formulas for quick revision.
- CBSE Boards: 3 marks - one question on binding energy, decay law, or Q-value.
- JEE Main: 2-3 questions per session on half-life, activity, and mass defect numericals.
- NEET: 1-2 questions per year on radioactive decay and nuclear radius formulas.
All Formulas for Nuclei - Class 12 Physics Chapter 13
The 9 formulas below cover every numerical in the chapter. Each row gives the concept, the formula, and the SI unit. Students preparing for CBSE need all 9. JEE Main adds 2-3 derived extensions flagged in the PDF.
| Concept | Formula | SI Unit |
|---|---|---|
| Nuclear radius | R = R_0 A^(1/3); R_0 = 1.2 fm | metre |
| Mass-energy equivalence | E = m c² | joule |
| Mass defect | delta m = sum nucleon masses - M_nucleus | kg |
| Binding energy | E_B = (delta m) c² | joule |
| Radioactive decay law | N = N_0 e^(-lambda t) | n/a |
| Half-life | t_half = 0.693 / lambda | second |
| Mean life | tau = 1 / lambda | second |
| Activity | A = lambda N | becquerel |
| Q-value | Q = (m_reactants - m_products) c² | joule |
Nuclei Class 12 Physics - Video Lecture
Source: JEE Wallah on YouTube
E = delta-m c² - mass defect converts to nuclear binding energy.
Topic-by-Topic Formula Breakdown for Nuclei - Class 12 Physics Chapter 13
The chapter divides into 6 sub-topic blocks. Each block carries its own formula and exam pattern:
- Nuclear composition and size: 1-mark on Z, N, A; R = R_0 A^(1/3)
- Mass-energy equivalence: 2-mark on E = mc²
- Binding energy and B/A curve: 3-mark on peak at A = 56
- Radioactivity and decay law: 2-mark on N = N_0 e^(-lambda t)
- Half-life and mean life: 3-mark on t_half = 0.693 / lambda
- Nuclear fission and fusion: 3-mark on Q-value and chain reaction
Nuclei Weightage Compared Across Class 12 Physics Chapters
The table below shows how Chapter 13 Nuclei marks compare with every other chapter. Marks are CBSE board averages over the last five papers.
| Chapter | Topic | Avg CBSE Marks |
|---|---|---|
| Ch 1 | Electric Charges and Fields | 6 marks |
| Ch 2 | Electrostatic Potential and Capacitance | 7 marks |
| Ch 3 | Current Electricity | 7 marks |
| Ch 4 | Moving Charges and Magnetism | 6 marks |
| Ch 5 | Magnetism and Matter | 3 marks |
| Ch 6 | Electromagnetic Induction | 5 marks |
| Ch 7 | Alternating Current | 6 marks |
| Ch 8 | Electromagnetic Waves | 2 marks |
| Ch 9 | Ray Optics and Optical Instruments | 7 marks |
| Ch 10 | Wave Optics | 5 marks |
| Ch 11 | Dual Nature of Radiation and Matter | 4 marks |
| Ch 12 | Atoms | 3 marks |
| Ch 13 | Nuclei | 3 marks |
| Ch 14 | Semiconductor Electronics | 6 marks |
Nuclei Previous Year Questions Weightage (2021 to 2026)
The table below maps every CBSE Board, JEE Main, and NEET appearance of Chapter 13 Nuclei topics over the last six sessions.
| Year | CBSE Board | JEE Main | NEET |
|---|---|---|---|
| 2026 | Binding energy per nucleon curve (3 marks) | Q-value of fusion reaction (4 marks) | Binding energy and radioactivity (2 questions) |
| 2025 | Radioactive decay law (3 marks) | Half-life and mean life relation | Nuclear fission energy MCQ |
| 2024 | Mass defect and binding energy (3 marks) | Activity of a sample | Beta decay particle MCQ |
| 2023 | Q-value of nuclear reaction (3 marks) | Carbon-14 dating numerical | Alpha particle range |
| 2022 | Half-life numerical (2 marks) | Binding energy of deuteron | Nuclear radius formula |
| 2021 | - | Decay constant calculation | Gamma-ray penetration |
Common Mistakes in Nuclei Formulas - Class 12 Physics Chapter 13
Mistake 1: Substituting values before simplifying the formula. Always rearrange to isolate the unknown first.
Mistake 2: Forgetting unit conversion. Use SI units everywhere unless the question specifies otherwise.
Mistake 3: Using approximate constants. For 5-mark numericals, use the exact value given in the question.
Mistake 4: Confusing half-life with mean life. Remember: tau = 1/lambda and t_half = 0.693/lambda, so tau is always larger than t_half.
Each mistake costs 1 to 2 marks in CBSE.
Nuclear numbers - binding energy, radius, half-life.
Student Feedback
- 74% of students surveyed placed the formula sheet at the top of their revision priority list.
- 58% reviewed the formula sheet daily in the last 7 days before the boards.
- 4 out of 5 students keep a printed copy in their notebook.
- Average revision time per formula sheet: 12 minutes per chapter for a focused pass.
- 67% used the formula sheet alongside Chapter Notes during the night-before revision pass.
Source: 2025-26 Class 12 Physics student poll. Sample of 11,030 students from CBSE schools across 16 states.
Other Resources for Class 12 Physics Nuclei
| Resource | Link |
|---|---|
| NCERT Solutions | Class 12 Nuclei NCERT Solutions |
| Chapter Notes | Class 12 Nuclei Notes |
| Formula Sheet | Class 12 Nuclei Formula Sheet |
| Handwritten Notes | Class 12 Nuclei Handwritten Notes |
| NCERT Book PDF | Class 12 Nuclei NCERT Book PDF |
| Exemplar Solutions | Class 12 Nuclei NCERT Exemplar Solutions |
NCERT Formula Sheets for Class 12 Physics: All Chapters
| Chapter | Resource |
|---|---|
| Chapter 1 | Electric Charges and Fields Formula Sheet |
| Chapter 2 | Electrostatic Potential and Capacitance Formula Sheet |
| Chapter 3 | Current Electricity Formula Sheet |
| Chapter 4 | Moving Charges and Magnetism Formula Sheet |
| Chapter 5 | Magnetism and Matter Formula Sheet |
| Chapter 6 | Electromagnetic Induction Formula Sheet |
| Chapter 7 | Alternating Current Formula Sheet |
| Chapter 8 | Electromagnetic Waves Formula Sheet |
| Chapter 9 | Ray Optics and Optical Instruments Formula Sheet |
| Chapter 10 | Wave Optics Formula Sheet |
| Chapter 11 | Dual Nature of Radiation and Matter Formula Sheet |
| Chapter 12 | Atoms Formula Sheet |
| Chapter 13 | Nuclei Formula Sheet |
| Chapter 14 | Semiconductor Electronics Formula Sheet |
Class 12 Physics Chapter 13 Nuclei Formula Sheet FAQs
Ques. How many formulas are in the Nuclei formula sheet?
Ans. 9 formulas cover every numerical the chapter generates. The table above lists them with units. The PDF carries the same list on a single A4 page for night-before revision.
Ques. What is the weightage of Class 12 Physics Chapter 13 Nuclei?
Ans. Chapter 13 carries 3 marks in CBSE Class 12 Physics. JEE Main tests 2-3 numericals per session. NEET asks 1-2 questions per year. The formula sheet covers all formulas needed for each track.
Ques. Where can I download the Nuclei formula sheet PDF?
Ans. The Nuclei formula sheet PDF is available directly on this page via the flipbook above. Click any page to view it, or use the download link to save it for offline revision.
Ques. Are JEE Main extensions covered in this formula sheet?
Ans. Yes. The formula sheet includes 2-3 extensions that JEE Main and JEE Advanced test but CBSE Boards rarely ask. These are flagged in the PDF so students can skip them when revising for boards only.
Ques. What is the most-asked formula in Class 12 Nuclei?
Ans. The radioactive decay law N = N_0 e^(-lambda t) and binding energy formula E_B = (delta m) c² appear most often in CBSE and JEE Main. Both are in the table above.
Comments