Skip to main content
Super TutorResources
Chapter 27 of 30
QuestionsNotesFlashcardsSummaryFormulasQuizConceptsSyllabusPlan
Study Plan

Nuclear Fission and Fusion

NIOS · Class 12 · Physics

Step-by-step guide to study Nuclear Fission and Fusion in NIOS Class 12 Physics. Topics to cover, practice strategy, and time allocation.

45 questions32 flashcards5 concepts

Interactive on Super Tutor

Studying Nuclear Fission and Fusion? Get the full interactive chapter.

Quizzes, flashcards, AI doubt-solver and a step-by-step study plan — built for study plan and more.

Try Super Tutor — Free

1,000+ Class 12 students started this chapter today

A diagram illustrating the nuclear fusion process, where two light nuclei combine under extreme conditions to form a heavier, more stable nucleus, releasing a large amount of energy.
Super Tutor

Learn better with visuals Super Tutor has hundreds of illustrations like this across every chapter — all free to try.

Get started

Study Plan

1
Day 1–2

Learn the Theory

Read the textbook chapter carefully. Note down definitions, formulas, and key concepts.

2
Day 3

Practice Problems

Solve textbook exercises and additional practice questions. There are 45 questions available for this chapter.

3
Day 4

Revise & Test

Revise key formulas and concepts without looking at notes. Take a practice quiz to test your understanding. Mark weak areas for re-revision.

4
Day 7

Spaced Revision

Revisit Nuclear Fission and Fusion after a week. Use flashcards for quick recall. Solve previous year questions from this chapter.

What to Focus On

  • Chemical reactions involve valence electrons; nuclear reactions involve the nucleus itself.
  • Energy in chemical reactions: few eV; in nuclear reactions: few MeV (about 10⁶ times more).
  • Mass is practically conserved in chemical reactions (change ≈ 10⁻³⁵ kg).

  • Nuclear fission was discovered in 1938 by Hahn and Strassmann; explained by Meitner and Frisch.
  • In fission, a heavy nucleus splits into two lighter nuclei + 2-3 neutrons + ~200 MeV energy.
  • Key fission equation: ²³⁵U + n → ¹⁴¹Ba + ⁹²Kr + 3n + 200 MeV

  • A nuclear reactor maintains a controlled chain reaction with multiplication factor k = 1.
  • Components: Fuel rods, Moderator, Control rods, Coolant, Reflector, Pressure vessel, Radiation shield.
  • Fuel: Enriched uranium (3-5% ²³⁵U); Moderator: Heavy water, graphite; Control rods: Cadmium or Boron.

Common Mistakes to Avoid

Nuclear fission and nuclear fusion both release energy for the same reason — breaking bonds

Fusion releases less energy than fission because it involves smaller atoms

The moderator in a nuclear reactor slows down or stops the chain reaction

Memory Tips

Nuclear Fission — splitting of a heavy nucleus into two lighter fragments

Nuclear Fusion — combining two light nuclei to form a heavier nucleus

Conservation laws in nuclear reactions: Mass Number, Atomic Number, Energy, Momentum

Energy released in fission of U-235 is approximately 200 MeV

Want a personalised study plan?

Super Tutor creates a day-by-day plan for NIOS Class 12 Physics that adapts to your exam date and pace.

Create My Study Plan — Free

Frequently Asked Questions

What are the important topics in Nuclear Fission and Fusion for NIOS Class 12 Physics?
Key topics in Nuclear Fission and Fusion include Nuclear Fission and Fusion — Complete Concept Map, Mind map showing the major topics covered in the chapter — fission, fusion, conservation laws, and applications, Flowchart comparing chemical and nuclear reactions based on which part of the atom interacts and the resulting energy scale. These are the concepts NIOS Class 12 examiners draw on most — study them first, then practise related questions.
How to score full marks in Nuclear Fission and Fusion — NIOS Class 12 Physics?
Understand the core concepts first, then work through the 45 practice questions available for this chapter. Revise formulas and definitions regularly, and use flashcards for quick recall before the exam.

Sources & Official References

Content is aligned to the official syllabus. Refer to the board website for the latest curriculum.

More resources for Nuclear Fission and Fusion

All 30 chapters — NIOS Class 12 Physics Study Plan

For serious students

Get the full Nuclear Fission and Fusion chapter — for free.

Quizzes, flashcards, AI doubt-solver and a step-by-step study plan for NIOS Class 12 Physics.

Try Super Tutor Free
Try the full chapter — Free