Question

calculate the resistance of 1km long copper wire of radius 1mm (resistivity of copper is 1.72×10^-8 ohm metre​

Answer 1

Answer:

R = 5.474 ohms

Explanation:

resistance = R

radius = r

area = A = pi*r^2 (for a cylindrical CS area) = 3.14*1*10^-3*1*10^-3

length = l

resistivity = P

R = (P*l)/A

R = (1.72*10^-8*1*10^3)/(3.14*10^-3*10^-3)

R = 5.474 ohms

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