Two parallel, very long wires 1 and 2 are separated by a distance r and carry currents of I1 = 3.5 A and I2 = 2.5 A. The magnitude of the force on a 4 m section of wire 2 due to the magnetic field produced by the current in wire 1 when the currents flow in opposite directions is F = 5.0×10−4 N, calculate the distance r. a. 4 m b. 28 cm c. 14 mm d. 14 cm e. None of the above.