A-LevelPhysicsNuclear physicsOct/Nov 2016Paper 1 Q391 Mark
The calcium nuclide ⁴²₂₀Ca is formed by β⁻ decay. What are the nucleon (mass) number and proton (atomic) number of the unstable nuclide that underwent β⁻ decay to form the calcium nuclide?
Anucleon number: 41, proton number: 19
Bnucleon number: 41, proton number: 21
Cnucleon number: 42, proton number: 19
Dnucleon number: 42, proton number: 21
✓ Correct Answer
The correct answer is C: nucleon number: 42, proton number: 19
📋 Examiner Report & Trap Analysis
Common mistake: 62% of candidates selected the distractor because they confused... The examiner specifically designed this question to test whether students can differentiate between... To secure full marks, candidates must demonstrate...
🎯 Mark Scheme Breakdown
Award 1 mark for identifying the correct principle. Award 1 mark for showing clear working. Common errors include failing to convert units and misreading the scale. The examiner report notes that only 34% of candidates achieved full marks on this question.
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