Two long resistance-free parallel wires of length L and radius a are placed at a distance d (with a < < d < < L) from each other, see figure. They are connected to a battery V on one end and resistor R on the other, see figure. Hence, current 1 = V/R is flowing through both wires, and the wires get charged to +V/C, where C is the capacitance of the wires. Find the resistance R at which the wires do not produce force on each other. V d I 2a R ww 12a