A Voice Coil It was shown in Section 27.7 that the net force on a current loop in a uniform magnetic field is zero. The magnetic force on the voice coil of a loudspeaker (see Fig) is nonzero because the magnetic field at the coil is not uniform. A voice coil in a loudspeaker bas 50 turns of wire and a diameter of 1.56 cm, and the current in the coil is 0.950 A. Assume that the magnetic field at each point of the coil has a constant magnitude of 0.220 T and is directed at an angle of 60.0o outward from the normal to the plane of the coil (Fig.). Let the axis of the coil be in the y-direction. The current in the coil is in the direction shown (counter clockwise as viewed from a point above the coil on the y-axis). Calculate the magnitude and direction of the net magnetic force on the coil.

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