Question

Calculate the resistance of a 200 m long copper wire, whose diameter is 1 mm. Given that the resistivity of copper is 1.7x10-8Ω m at 0°C.

Answer 1

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Answer 2

Answer:

Explanation:

Length of the copper wire l = 200 m

       Diameter of the copper wire = d = 1 mm = 1 x 10−3 m

       Radius of the copper wire r = d/2 = 5 x  10−4 m

       Area of cross section of the copper wire A = π r2 = 3.14 x (5 x  10−4 m)2

                                                                                       =78.5 x  10−8 m2

      Resistivity of copper ρ = 1.7 x 10-8 Ωm

      Resistance of the copper wire R = ρl/A =

      = 1.7 x 10-8 Ωm x 200 m/(78.5 x 10−8 m2)

      = 4.33 Ω