A-LevelPhysicsSuperpositionMay/June 2018Paper 1 Q261 Mark
The diagram shows apparatus for the measurement of the frequency of a sound wave. [Diagram] Sound of the unknown frequency is reflected back from a metal plate. A microphone placed at a distance D from the metal plate detects the sound intensity. A minimum intensity is detected with D = 12.0 cm. The plate is moved further away from the microphone until the next minimum is detected with D = 15.0 cm. The speed of sound in air is 336 ms⁻¹. What is the frequency of the sound?
A56 Hz
B112 Hz
C5600 Hz
D11200 Hz
✓ Correct Answer
The correct answer is C: 5600 Hz
📋 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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