Exam-style question
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Explain how the length of a wire affects its resistance. Include a relevant formula in your explanation.
Model answer
What a good answer should say
- The resistance of a wire increases with its length.
- This is described by the formula R = ρ(L/A), where R is resistance, ρ is resistivity, L is the length of the wire, and A is the cross-sectional area.
- As the length (L) increases, the resistance (R) increases proportionally, assuming resistivity and cross-sectional area remain constant.
Explanation
Why this works
This answer is strong because it directly addresses the relationship between length and resistance using the appropriate formula. It tests the understanding of how physical dimensions of a conductor influence its electrical properties, which is a key concept in resistivity.
Common mistake
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