Table 12.1 Room-Temperature Electrical Conductivities for Nine Common Metals and Alloys Metal Electrical Conductivity ((12m)-1] 6.8 x 107 Silver 6.0 x 107 Copper Gold 4.3 * 107 3.8 x 107 Aluminum Brass (70 Cu-30 Zn) 1.6 x 107 Iron 1.0 x 107 Platinum 0.94 * 107 Plain carbon steel 0.6 x 107 Stainless steel 0.2 x 107 (a) Using the data in Table 12.1, compute the resistance of a copper wire 4 mm (0.16 in.) in diameter and 5 m (197 in.) long. i (b) What would be the current flow if the potential drop across the ends of the wire is 0.04 V? i A (c) What is the current density? A/m2 (d) What is the magnitude of the electric field across the ends of the wire? i V/m