Exam-style question
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During the decay β⁻ + p → n + β⁻, which conservation law is explicitly satisfied by the presence of the outgoing β⁻?.
- A.Conservation of charge
- B.Conservation of baryon number
- C.Conservation of lepton number
- D.Conservation of energy
Model answer
What a good answer should say
- Conservation of lepton number.
- the correct option
Explanation
Why this works
The correct answer is Conservation of lepton number. It is the only option that matches the AQA A-Level Physics requirement for Applications of conservation laws; the distractors either apply to a different particle concept or reverse the relationship being tested.
Common mistake
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