Two identical metal wires are laid - as shown in the figure in the x-y plane at a distance of - d = 10 m. Each wire has a circular cross- sectional area with a diameter of D = 20 mm and is allowed here for a maximum current density of j_m= 1 A/mm. A current I flows through each wire along the x-axis. The direction of the current flow through the two wires is opposite (see figure). Note: For both wires, the current density is homogeneously distributed over the cross-section of the wire. d 4 a) Determine the maximum allowed current I_m that can flow through each wire. b) Determine the strength and direction of the magnetic field generated by the first wire with current flow I_m at the location of the second wire. c) Assuming each wire is flowing with the maximum allowed current I_m, what is the force per unit length between the wires? d) Is this force repulsive or attractive?