Exam-style question
Try this first
In the reaction β⁻ + p → n + β⁻, what is the net change in lepton number?.
- A.+1
- B.0
- C.–1
- D.+2
Model answer
What a good answer should say
- 0.
- the correct option
Explanation
Why this works
The correct answer is 0. 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
No common mistake is linked to this question yet.