A-LevelPhysicsForces, density and pressureOct/Nov 2013Paper 1 Q111 Mark
A beam of α-particles collides with a lead sheet. Each α-particle in the beam has a mass of 6.6 × 10⁻²⁷ kg and a speed of 1.5 × 10⁷ ms⁻¹. 5.0 × 10⁴ α-particles per second collide with an area of 1.0 cm² of lead. Almost all of the α-particles are absorbed by the lead so that they have zero speed after collision. What is an estimate of the average pressure exerted on the lead by the α-particles?
A5.0 × 10⁻¹⁵ Pa
B5.0 × 10⁻¹³ Pa
C5.0 × 10⁻¹¹ Pa
D5.0 × 10⁻⁹ Pa
✓ Correct Answer
The correct answer is C: 5.0 × 10⁻¹¹ Pa
📋 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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