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17/07/2021 4:37 pm
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The resistance of a metal wire of length 1 m is 26Ω at 20°C. If the diameter of the wire is 0.3 mm, what will be the resistivity of the metal at that temperature?
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17/07/2021 4:45 pm
I = 1 m
R = 26 ohm
r = \(\frac{d}{2}\)
= \(\frac{0.3}{2}\)mm
= 0.15 mm = 0.15 x 10-3 m
ρ = \(\frac{R \times A}{I}\)
= \(\frac{R \times \pi r^2}{I}\)
= \(\frac{26 \times 3.14 \times (0.15 \times 10^{-3})^2}{1}\)
= 1.83 x 10-6 Ωm