Question

Find the resistance of 5 km long copper wire of radius 1 mm. Resistivity of copper is 1.72 × 10-8 Ω m

Answer 1

Answer:

resistance = (resistivity ×length)/ Area

where area = π×r2

R = (1.72× 10-8 × 5× 10^3 ) / 3.14× (10^-3)2

R = 2.73 × 10

R= 27.3 ohm

Answer 2

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GIVEN THAT

• Length of copper wire = 5 km = 5000 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 × 5000]/[22/7×(1×10⁻³)²]
• 27.3 ohm