Question

Calculate the resistance of 1 km long copper wire of radius 1 mm. (Resistivity of copper = 1.72 × 10 -8 )

Answer 1

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Answer 2

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GIVEN THAT

• Length of copper wire = 1 km = 1000 m
• Radius of copper wire = 1 mm = 1 × 10-³ m
• Resistivity of copper = 1.72 x 10⁻⁸

CALCULATION OF RESISTANCE

• (Resistivity of copper × Length)/(Area)
• (Resistivity of copper × Length)/(πr²)
• [1.72×10⁻⁸*1000]/[22/7×(1×10⁻³)²]
• 5.5 ohm