A copper cable needs to carry a current of 250 A with a power loss of only 3 W/m.What is the required radius of the copper cable? (The resistivity of copper is 1.7 × 10−⁸ Ω⋅m).

Question

Quizplus · Accepted Answer

To find the radius, use the formula for power loss per unit length: P = I²R, where R = ρL/A. Rearrange to find A = ρI²/P. Substitute the given values: ρ = 1.7 × 10⁻⁸ Ω⋅m, I = 250 A, P = 3 W/m. Solve for A, then use A = πr² to find r. The correct radius is approximately 1.06 cm.

A Copper Cable Needs to Carry a Current of 250