Nuclear Reactions
Balance nuclear changes and use mass–energy reasoning for radioactive decay, fission and fusion.
How to study Higher Physics
Move between physical models, relationships, units, graphs and justified conclusions, while using current official materials for exact paper and assignment conditions.
Core concepts
Concept 1
nuclear equations for radioactive decay
Exam cue: Conserve nucleon number and charge in every nuclear equation.
Concept 2
spontaneous and induced fission, and fusion
Exam cue: Convert mass to kilograms before using E = mc².
Concept 3
mass defect and E = mc²
Exam cue: Connect released energy to the loss of mass across the reaction.
Concept 4
high-temperature plasma and magnetic confinement in fusion reactors
Risk pitfalls and guardrails
Failing to conserve both nucleon number and charge in a nuclear equation.
Guardrail: Check assumptions, prefixes, units, significant figures and whether the statement is supported by evidence.
Confusing fission with fusion.
Guardrail: Check assumptions, prefixes, units, significant figures and whether the statement is supported by evidence.
Omitting the high temperature or magnetic containment needed for a fusion-reactor plasma.
Guardrail: Check assumptions, prefixes, units, significant figures and whether the statement is supported by evidence.
Memory anchors
Alpha decay
Mass number falls by 4 and atomic number falls by 2.
Beta-minus decay
A neutron becomes a proton, electron and antineutrino; atomic number rises by 1.
Mass–energy
E = mc².
Fission
A heavy nucleus splits into smaller nuclei with released energy and usually neutrons.
Fusion
Light nuclei combine; high temperature helps them overcome electrostatic repulsion.
Fusion-reactor conditions
Very high temperature forms a plasma; magnetic fields contain the charged particles.
Checkpoint rule
Do the check-up only after you can summarize each concept in one sentence and identify one dangerous pitfall from memory.
Knowledge Check (after reading)
Short check-up to confirm understanding of this module.
Check-up Questions
In an alpha decay, how do the parent nucleus's mass number and atomic number change?
In β⁻ decay, what happens to the nucleus's mass number and atomic number?
Answer all questions to submit.
Next step personalized recommendations
Continue learning
Move forward only after this module is stable.
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