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16/07/2021 5:52 pm
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Calculate the resistance of a copper wire 1.0 km long and 0.50 mm diameter if the resistivity of copper is 1.7 × 10-8 Ωm.
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16/07/2021 5:57 pm
I = 1 km = 1000 m
r = d/2 = 0.5/2 mm = 0.25 mm
= 0.25 x 10-3 m
\( \rho \) = 1.7 x 10-8 Ωm
R = \( \rho\) \(\frac{I}{A}\) = \( \rho \frac{I}{\pi r^2} \)
R = \(1.7 \times 10^{-8} \times \frac{1000}{3.14 \times (0.25 \times 10^{-3})^2} \)
= 86.6 Ω