An iron wire and a copper wire of the same length have the same potential difference applied to them. What must be the ratio of their radii if the currents in the two wires are to be the same? (Ratio of the radius of iron wire to that of copper wire). For the resistivities of iron and copper use: rhoiron = 1.0 times 10-7 capital omega m; rhocopper = 1.7 times 10-8 capital omega m;