Four long, parallel wires are located at the corners of a square of side a = 30 cm, as shown in the figure I4 = 4 A. Find: a) the resultant magnetic field at the center of the square: (i+i+k) T. b) the force on an electron moving at 6 x 100 m/s as it passes the center: 4 where I = 11 A, I2 = 3 A, I3 = 6 A, 11 12 (X) N 13