Chapter 26 of 30
Concept Maps
Nuclei and Radioactivity — Concept Maps
NIOS · Class 12 · Physics
4 concept maps of Nuclei and Radioactivity for NIOS Class 12 Physics, each also written out as a text outline. Part of the NIOS Class 12 Physics syllabus.
45 questions36 flashcards18 formulas & key relations5 concepts
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4 Concept Maps
Chapter Overview – Nuclei and Radioactivity
The map in words
- Nuclei and Radioactivity
- Nuclear Structure
- Protons and Neutrons
- Atomic Number Z
- Mass Number A
- Neutron Number N equals A minus Z
- Nuclear Notation
- Isotopes same Z
- Isobars same A
- Isotones same N
- Nuclear Size
- R equals r0 times A one third
- r0 equals 1.2 fermi
- Nuclear Density
- 2.3 times 10 to 17 kg per m3
- Constant for all nuclei
- Atomic Mass Units
- 1 u equals 1.66 times 10 to minus 27 kg
- 1 u equals 931.3 MeV
- Proton mass 1.00727 u
- Neutron mass 1.00865 u
- Mass Defect and Binding Energy
- Mass Defect delta m
- Sum of nucleon masses minus nuclear mass
- Binding Energy BE
- BE equals delta m times 931.3 MeV
- Binding Energy per Nucleon B
- B equals BE divided by A
- Maximum at Iron A equals 56
- Explains Fission and Fusion
- Mass Defect delta m
- Nuclear Forces
- Short Range
- Very Strong
- Charge Independent
- Saturating
- Repulsive at very short range
- Radioactivity
- Discovery by Becquerel 1896
- Marie Curie isolated Radium
- Types of Radiation
- Alpha Particle
- Helium nucleus 4 2 He
- High ionizing power
- Low penetration
- Beta Particle
- Electrons or Positrons
- Moderate ionizing
- Moderate penetration
- Gamma Rays
- Electromagnetic waves
- Low ionizing power
- High penetration
- Alpha Particle
- Radioactive Decay Laws
- dN by dt equals minus lambda N
- N equals N0 times e to minus lambda t
- Half Life T half equals 0.693 by lambda
- Mean Life Ta equals 1 by lambda
- Applications
- Carbon Dating
- Radiotherapy
- Tracer Technique
- Industrial Flaw Detection
- Agriculture
- Nuclear Structure
Correct vs Incorrect Thinking in Radioactive Decay
The map in words
- Radioactive Nucleus
- Type of Decay?
- Alpha Decay: A decreases by 4\nZ decreases by 2
- New element formed\nDifferent Z and A
- External temp or pressure\nNO effect on any decay
- WRONG: Decay rate\nchanges with temperature
- CORRECT: Lambda is\nfixed for each nucleus
- External temp or pressure\nNO effect on any decay
- New element formed\nDifferent Z and A
- Beta-Minus Decay: A stays SAME\nZ increases by 1
- New element formed\nSame A different Z
- Gamma Decay: A stays SAME\nZ stays SAME
- Same nucleus\nLower energy state
- Alpha Decay: A decreases by 4\nZ decreases by 2
- Type of Decay?
Nuclei and Radioactivity — Complete Chapter Mind Map
The map in words
- Nuclei and Radioactivity
- Nuclear Structure
- Protons and Neutrons
- Z = Atomic Number
- A = Mass Number
- N = A minus Z
- Nuclear Notation
- Isotopes same Z
- Isobars same A
- Isotones same N
- Nuclear Size
- R = r0 times A one-third
- r0 = 1.2 fm
- Density = 2.3e17 kg per cubic metre
- Protons and Neutrons
- Atomic Mass and Units
- 1 u = 1.66e-27 kg
- 1 u = 931.3 MeV
- mp = 1.00727 u
- mn = 1.00865 u
- Mass Defect and Binding Energy
- Mass Defect delta-m
- Free nucleons minus nucleus mass
- Total BE = delta-m times c squared
- BE per nucleon = BE divided by A
- Stability
- Peak at Fe-56 = 8.8 MeV
- Fission releases energy
- Fusion releases energy
- Mass Defect delta-m
- Nuclear Force
- Strongest force
- Short range 10 to -15 m
- Charge independent
- Saturation property
- Repulsive at very small r
- Radioactivity
- Discovery
- Becquerel 1896
- Marie Curie radium
- Types of Radiation
- Alpha = He nucleus
- Beta = electron or positron
- Gamma = EM wave
- Decay Laws
- dN by dt = minus lambda N
- N = N0 times exp minus lambda t
- T half = 0.693 divided by lambda
- Units of Activity
- Becquerel 1 per second
- Curie 3.7e10 per second
- Rutherford 1e6 per second
- Discovery
- Applications
- Medicine tracer technique
- Carbon Dating T-half 5730 years
- Agriculture gamma irradiation
- Industry flaw detection
- Geology age of earth
- Nuclear Structure
Atomic Nucleus
The map in words
- Atomic Nucleus
- Nuclear Composition
- Nuclear Notation and Classification
- Nuclear Size and Density
- Unified Atomic Mass Unit
- Mass Defect and Binding Energy
- Nuclear Force
- Radioactivity
- Types of Radiation
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Explore DiagramsFrequently Asked Questions
What are the important topics in Nuclei and Radioactivity for NIOS Class 12 Physics?
Key topics in Nuclei and Radioactivity include The Atomic Nucleus – Structure and Properties, Mass Defect and Binding Energy, Nuclear Forces, Radioactivity – Discovery and Nature of Radiation. Study these first, then practise questions on each for the NIOS Class 12 board exam.
What do the concept maps for Nuclei and Radioactivity show?
The 4 maps show how the ideas in Nuclei and Radioactivity connect: Chapter Overview – Nuclei and Radioactivity; Correct vs Incorrect Thinking in Radioactive Decay. Each map is also written out as an outline on this page.
How should I revise Nuclei and Radioactivity for the NIOS Class 12 board exam?
Learn the core ideas first, then work through the 45 practice questions on Nuclei and Radioactivity. Revise 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.
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Important Questions
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Revision Notes
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Formula Sheet
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Chapter Summary
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Study Plan
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Flashcards
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Syllabus
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