A-LevelPhysicsElectricityOct/Nov 2010Paper 1 Q341 Mark
A wire PQ is made of three different materials, with resistivities ρ, 2ρ and 3ρ. There is a current I in this composite wire, as shown. [Figure showing a wire PQ composed of three segments with resistivities ρ, 2ρ, 3ρ respectively.] Which graph best shows how the potential V along the wire varies with distance x from P?
AGraph showing potential V decreasing linearly with distance x (constant gradient).
BGraph showing potential V decreasing piecewise linearly with distance x, with three segments of increasing negative gradient (magnitude of slope).
CGraph showing potential V decreasing non-linearly with distance x.
DGraph showing potential V decreasing in three distinct steps with distance x.
✓ Correct Answer
The correct answer is B. This question tests the candidate's understanding of electricity 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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