Question

A 100 m copper wire 2 mm in diameter has a 1.0 A current inside. The copper wire is joined end to end to a 114 m long iron wire of the same diameter. Find the potential drop across the iron wire, ρIron = 9.7x10-8 Ω-m.

Answer 1

Riron = (ρIron * L)/A
Riron = (9.7*10^-8 * 114)/(π * 1/4 * (2.0*10^-3)^2)
Riron = 3.52 Ω

V = I * Riron
V = 1 * 3.52 v
V = 3.52 v
Potential drop across the iron wire, V = 3.52 v