일반물리학 2 — Magnetic Fields Due to Currents: Problem 44

44 Figure 29-49 shows, in cross section, two long straight wires held against a plastic cylinder of radius 15.0 cm. Wire 1 carries current \( i_1 = 60.0 \text{ mA} \) out of the page and is fixed in place at the left side of the cylinder. Wire 2 carries current \( i_2 = 40.0 \text{ mA} \) out of the page and can be moved around the cylinder. At what (positive) angle \( \theta_2 \) should wire 2 be positioned such that, at the origin, the net magnetic field due to the two currents has magnitude 80.0 nT?