Problem 17.57 (Multistep)
A bar magnet with magnetic dipole moment 0.46 A · m² lies on the negative x axis, as shown in the figure below. A compass is located at the origin. Magnetic north is in the negative z direction. Between the bar magnet and the compass is a coil of wire of radius 3.5 cm, connected to batteries not shown. The distance from the center of the coil to the center of the compass is 8.8 cm. The distance from the center of the bar magnet to the center of the compass is 22.6 cm. A steady current of 0.96 A runs through the coil. Conventional current runs clockwise in the coil when viewed from the location of the compass. (Assume the z ≫ R approximation for the coil applies.)
Despite the presence of the coil and the bar magnet, the compass points north.
(c) How many turns of wire are in the coil?