In Figure (a), two circular loops with different currents but the same radius of 10. cm, are centered on a y axis. They are initially separated by distance L = 7.5 cm, with loop 2 positioned at the origin of the axis. The currents in the two loops produce a net magnetic field at the origin, with y component By. That component is to be measured as loop 2 is gradually moved in the positive direction of the y axis. Figure (b) gives By as a function of the position y of loop 2. The horizontal axis is marked in increments of 5 cm, the vertical axis is marked in increments of 5 µT, and the curve approaches an asymptote of By = 1.9 µT as y infinity.