A-LevelPhysicsPhysical quantities and unitsMay/June 2018Paper 1 Q21 Mark

The drag coefficient Cd is a number with no units. It is used to compare the drag on different cars at different speeds. Cd is given by the equation Cd = (2F)/(vⁿρA) where F is the drag force on the car, ρ is the density of the air, A is the cross-sectional area of the car and v is the speed of the car. What is the value of n?

Q: What topic does this question test?

This question tests Physical quantities and units in A-Level Physics (syllabus code 9702). It is worth 1 mark.

✓ Correct Answer

The correct answer is B: 2

📋 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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About This A-Level Physics Question

Topic

This multiple-choice question tests Physical quantities and units in A-Level Physics (syllabus code 9702). It is worth 1 mark.

Source

This question appeared in the Cambridge A-Level Physics May/June 2018 examination, Paper 1 Variant 2.

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