In the figure, four long straight wires are perpendicular to the page, and their cross sections form a square of edge length a = 21 cm. The currents are out of the page in wires 1 and 4 and into the page in wires 2 and 3, and each wire carries 20 A. What is the magnitude of the net magnetic field at the square's center? - X Number i Units TIn the figure, four long straight wires are perpendicular to the page, and their cross sections form a square of edge length a = 14.0 cm. Each wire carries 7.00 A, and the currents are out of the page in wires 1 and 4 and into the page in wires 2 and 3. In unit-vector notation, what is the net magnetic force per meter of wire length on wire 4? Number i + Units