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Question
A wire is 1.0 m long, 0.2 mm in diameter and has a resistance of 10 Ω. Calculate the resistivity of its material?
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Solution
Given length of the wire, l = 1 m
Diameter of the wire, d = 0.2 mm
So the radius of the wire, r = 0.1 mm = 0.0001 m
Area of cross-section of the wire, = `A=pir^2=3.14xx(0.0001)^2=3.14xx10^-8m^2`Resistance of the wire R=10 Ω
So resistivity `=rho=(RA)/l`
`rho=3.14xx1^7 `Ωm
Thus,the resistivity of the material,`rho=3.14xx10^-7` Ωm
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