Exam-style question
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A wire has a length of 2 m and a cross-sectional area of 1 mm². If the resistivity of the material is 1.68 x 10^-8 Ωm, calculate the resistance of the wire.
Model answer
What a good answer should say
- The resistance of the wire is 0.0336 Ω.
Explanation
Why this works
The correct answer is The resistance of the wire is 0.0336 Ω.. This is correct because it applies the Current electricity idea named in the question, using the required quantities and units rather than mixing current, charge, potential difference, resistance, power, or energy.
The other options are less suitable because they use the wrong electrical quantity, an incompatible unit, or a rule from a different circuit context.
Common mistake
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