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The resistance of an electric wire of an alloy is 102.If the thickness of wire is 0.001 m and length is 1 m,find its resistivity.[Ans. 7.85 x 10-42 m) |
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Answer» Given:Resistance(R)=10Ω, length(L)=1m, Diameter=0.001m, Radius (Diameter/2)=0.005m. The area of the cross section of the wire is π r^2 Or, A = 3.14 x (0.005)^2 m^2 Or, A = 0.0000785 m^2. We know that, ρ= (R*A)/L. Therefore, ρ= (10Ω*0.0000785)sqm / 1m. ρ=10Ω*0.0000785. ρ=0.000785Ωm. Therefore, the resistance is 0.000785Ωm. |
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