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Aluminium wire has radius 0.25 mm and length or 75 m. If the resistance of the wire is 10Ω, calculate the resistivity of aluminium. |
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Answer» The formula of resistance is: R = \(\frac{ρ\,\times\,I}{A}\) Where, ρ = resistivity I = Length of the conductor A = Area of the conductor ∴ ρ = \(\frac{R\,\times\,A}{I}\) Here: R = 10 Ω r = 0.25mm l = 75m We know that the area of the wire will be: A = πr2 ∴ A = 3.14 x (0.25 x 10-3)2 A = 0.196 x 10-6 m2 Putting the given values in the above formula ρ = \(\frac{10\,\times\,0.196\,\times\,10^{-6}}{75}\) ρ = 26.133 x 10-6 Am |
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