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When a metal rod is heated, not only its resistance but also its length and cross-sectional area change. The relation R = pL/A suggests that all three factors should be taken into account in measuring ρ at various temperatures. If the temperature changes by 1.0 C°, what percentage changes in (a) L, (b) A, and (c) R occur for a copper conductor? (d) What conclusion do you draw? The coefficient of linear expansion is 1.70 × 10–5 K–1.
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