A-LevelPhysicsD.C. circuitsFeb/Mar 2020Paper 1 Q351 Mark
Two batteries are connected together, as shown. [Figure showing battery 1 (12 V, 0.3 Ω internal resistance) and battery 2 (9 V, 0.1 Ω internal resistance) connected in series, with their positive terminals connected together] Battery 1 has electromotive force (e.m.f.) 12 V and internal resistance 0.3 Ω. Battery 2 has e.m.f. 9 V and internal resistance 0.1 Ω. What are the e.m.f. and the internal resistance of a single battery that has the same effect as the combination?
A3 0.2
B3 0.4
C21 0.2
D21 0.4
✓ Correct Answer
The correct answer is B: 3 0.4
📋 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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