Question

Calculate the resistance of 1km long copper wire of radius 1mm.Resistivity of the copper is 1.27×10'8

Answer 1

Answer:

5.48Ω

Explanation:

Here, length of the wire, l=1km=1000m

radius of the wire, r=1mm= $10^{-3}$m,

resistivity of cooper, ρ= 1.72×$10^{-8}$Ωm

cross-sectional area of the wire, A=πr^2

=3.14×(10^−3)^2

=3.14×10−6m2

If R is the resistance of the given wire, then

R=ρlA

=(1.72×10−8Ωm)×(1000m)3.14×10−6m2

=5.48Ω