Copper and aluminum are being considered for a high-voltage transmission line that must carry a current of 76.5 A. The resistance per unit length is to be 0.155 Ω/km. The densities of copper and aluminum are 8960 and 2600 kg/m3, respectively. Compute (a) the magnitude J of the current density and (b) the mass per unit length λ for a copper cable and (c) J and (d) λ for an aluminum cable. (a) Number Units (b) Number Units (c) Number Units (d) Number Units