A-LevelPhysicsPhysical quantities and unitsMay/June 2015Paper 1 Q31 Mark
An analogue ammeter has a pointer which moves over a scale. Following prolonged use, the pointer does not return fully to zero when the current is turned off and the meter has become less sensitive at higher currents than it is at lower currents. Which diagram best represents the calibration graph needed to obtain an accurate current reading?
A[Diagram A: Scale reading vs true current, curve starting at (0,0) and bending downwards, representing decreasing sensitivity.]
B[Diagram B: Scale reading vs true current, curve starting at (0,0) and bending upwards, representing increasing sensitivity.]
C[Diagram C: Scale reading vs true current, curve starting above (0,0) and bending downwards, representing a zero error and decreasing sensitivity.]
D[Diagram D: Scale reading vs true current, curve starting above (0,0) and bending upwards, representing a zero error and increasing sensitivity.]
✓ Correct Answer
The correct answer is C. This question tests the candidate's understanding of physical quantities and units within the Physicssyllabus. The examiner's mark scheme requires...
📋 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...
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