A-LevelPhysicsD.C. circuitsMay/June 2014Paper 1 Q351 Mark
A power supply and a solar cell are compared using the potentiometer circuit shown. [Figure 35.1] The e.m.f. produced by the solar cell is measured on the potentiometer. The potentiometer wire PQ is 100.0 cm long and has a resistance of 5.00 Ω. The power supply has an e.m.f. of 2.000 V and the solar cell has an e.m.f. of 5.00 mV. Which resistance R must be used so that the galvanometer reads zero when PS = 40.0 cm?
A395 Ω
B795 Ω
C995 Ω
D1055 Ω
✓ Correct Answer
The correct answer is B: 795 Ω
📋 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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