A-LevelPhysicsElectric fieldsFeb/Mar 2020Paper 1 Q311 Mark
A negatively charged oil drop is held stationary, equidistant between two plates connected to a high voltage supply, as shown. [Figure showing a negatively charged oil drop held stationary between two parallel plates, with the top plate positive and bottom plate negative] Which change would not increase the upward electrical force on the drop?
Adecreasing the distance between the plates whilst keeping the drop equidistant from them
Bincreasing the amount of negative charge on the drop
Cincreasing the supply voltage
Dmoving the drop closer to the positive plate
✓ Correct Answer
The correct answer is D: moving the drop closer to the positive plate
📋 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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