An iron bar is used to try to pick up some paperclips or thumbtacks. It is not able to do this because it is not magnetized. The rod is placed in a long solenoid and DC power applied. The rod becomes magnetized and is able to pick up some of the paperclips or tacks. The rod is again placed inside the solenoid and 120 VAC applied. This demagnetizes the rod and it will not pickup any tacks.
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