Question

Calculate resistance of 1 km long copper wire of radius 1 mm

Answer 1

Explanation:

Resistivity of copper is 1.72×10-8Ωm. If R is the resistance of the given wire, then R=ρlA=(1.72×10-8Ωm)×(1000m)3. 14×10-6m2=5.48Ω