Calculate the resistance of 2 km long copper wire of radius 2 mm. (Resistivity of copper = 1.72 x 1 0-8)
Length of copper wire=2 km = 2000 m Radius of copper wire=2 mm = 2× Resistivity of copper=1.72x10⁻⁸ Resistance=(Resistivity of copper × Length)/(Area) Resistance=(Resistivity of copper × Length)/(πr²) Resistance=[1.72×10⁻⁸*2000]/[22/7×(2×10⁻³)²] Resistance=(0.0000344)/(22/7)(0.000004) Resistance=0.0000344/0.00001256 Resistance=2.73 ohm
