B₁, B₂ and B₃ are three identical lamps. They are connected to a battery with zero internal resistance, as shown. [Figure 30.1] Initially the switch is closed. The switch is then opened and lamp B₃ goes out. What happens to the brightness of lamps B₁ and B₂ when the switch is opened?
✓ Correct Answer
The correct answer is B: brightness of lamp B₁ decreases, brightness of lamp B₂ increases
📋 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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