Question

calculate the resistance of two kilometre long copper wire of radius 2 millimetre​

Answer 1

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 

Answer 2

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