What section should you take a copper wire 8.5 m long so that at a current of 150 A, the voltage at its ends is 6 V?

Task data: l (length of the taken copper wire) = 8.5 m; I (current) = 150 A; U (required voltage at the ends of the wire) = 6 V.

Reference values: ρ (specific electrical resistance of copper at normal conditions) = 0.017 Ohm * mm2 / m.

We express the required cross-section of a copper wire from the equality: ρ * l / S = R = U / I, whence S = ρ * l * I / U.

Calculation: S = 0.017 * 8.5 * 150/6 = 3.6125 mm2.

Answer: It is necessary to take a copper wire with a cross-sectional area of 3.6125 mm2.