A-LevelPhysicsElectric fieldsMay/June 2017Paper 1 Q311 Mark
The path of an electron with initial speed v in the uniform electric field between two parallel plates is shown. [Figure shows an electron entering horizontally between two horizontal parallel plates, being deflected downwards by an electric field. The vertical deflection at the right-hand edge is labelled x.] The vertical deflection x is measured at the right-hand edge of the plates. The distance between the plates is halved. The potential difference between the plates remains the same. What will be the new deflection of the electron with the same initial speed v?
Ax
B√2 x
C2x
D4x
✓ Correct Answer
The correct answer is C: 2x
📋 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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