A-LevelPhysicsElectric fieldsOct/Nov 2014Paper 1 Q281 Mark
The diagram shows two parallel horizontal metal plates. There is a potential difference V between the plates. [Figure 28.1] A small charged liquid drop, midway between the plates, is held in equilibrium by the combination of its weight and the electric force acting on it. The acceleration of free fall is g and the electric field strength is E. What is the polarity of the charge on the drop, and the ratio of charge to mass of the drop?
Apolarity negative, charge/mass E/g
Bpolarity negative, charge/mass g/E
Cpolarity positive, charge/mass E/g
Dpolarity positive, charge/mass g/E
✓ Correct Answer
The correct answer is B: polarity negative, charge/mass g/E
📋 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.
🔒
Unlock the Examiner's Analysis
Sign up for free to reveal the full examiner report, trap analysis, and mark scheme breakdown for this question.
Sign Up Free to Unlock →Join thousands of Cambridge students already using Oracle Prep