The four wires that lie at the corners of a square of side a= 4.20 cm are carrying equal currents i= 1.30 A into (+) or out of (-) the page, as shown in the picture.
A) Calculate the y component of the magnetic field at the center of the square.
B) Calculate the x-component of the force on a 1.0-cm long piece of the lower right-hand wire, due to the other three wires.