A magnet factory is making bar magnets, each about the size and shape of an ordinary ruler. After forming each bar of metal, that bar must be magnetized. The bar is placed in a coil of wire and a huge pulse of current is sent through the coil. During the pulse, current is only sent in one direction through the coil: a pulse of direct current or DC. If, instead, the current reversed directions rapidly during the pulse-a pulse of alternating current or AC-then
A) the bar magnet would end up with two south poles and no north poles.
B) the poles of the bar magnet would also reverse rapidly and would end up with a magnetization that depends upon what the AC current was at the precise moment it was shut off.
C) the bar would become overmagnetized because AC is much more magnetic than DC.
D) the bar magnet would end up with two north poles and no south poles.

Question

Quizplus · Accepted Answer

Using alternating current (AC) to magnetize a bar would cause the magnetic field direction in the bar to change direction rapidly, following the changes in the current's direction. The final magnetization of the bar would depend on the magnetic field direction at the moment the current is turned off, not resulting in a bar with two south or two north poles, nor in overmagnetization due to AC being "more magnetic" than DC.

A Magnet Factory Is Making Bar Magnets, Each About the Size