Question

The resistance of a metal wire of length 1m is 25 ohms at 20°C. If the diameter is 0.3 mm, what must be the resistivity of the metal at thet temperature?

Answer 1

resistivity
$resistivity \: = \frac{ra}{l} \\ = resistance \: \times \frac{\pi {r}^{2} }{l} \\ = 25 \times \frac{3.14 \times (0.3 \times {10}^{ - 3}) {}^{2} }{1} \\ = 25 \times 3.14 \times 0.09 \times {10}^{ - 6} \\ resistivity= 7.065 \times {10}^{ - 6} ohm \: metre$

Answer 2

Answer:

Explanation:

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