Magnets

Consequent poles

Consequent poles One should never assume, without prior test, that a bar magnet always has opposite poles at its ends. If a steel bar is magnetized by divided touch using two S poles we obtain a N pole at both ends of the bar and a double S pole ill the center. In this condition the bar is …

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To magnetize a steel bar by the methods of single and divided touch

To magnetize a steel bar by the methods of single and divided touch Before the magnetic effect of an electric current was discovered in the early nineteenth century magnets were made by stroking steel bars with a lodestone or with another magnet. There are two ways in which this may be done, called the methods of single …

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Magnetic and non-magnetic substances

Magnetic and non-magnetic substances Apart from iron, the other common elements which are attracted strongly by a magnet are cobalt and nickel. These, together with certain strongly magnetic alloys are described as ferromagnetic. Substances such as copper, brass, wood, and glass are not attracted by a magnet, and are commonly described as non-magnetic. Nevertheless, experiments with very powerful …

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Magnetic poles

Magnetic poles If a piece of lodestone is dipped into iron filings it is noticed that the filings cling in tufts, usually at two places in particular (Fig. 30.1). When the experiment is performed with a bar magnet the filings are seen to cling in tufts near the ends. Few, if any, filings are attracted to the …

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Magnets

Magnets As early as 600 B.C. the Greeks knew that a certain form of iron ore, now known as magnetite or lodestone, had the property of attracting small pieces of iron. Later, during the Middle Ages, crude navigational compasses were made by attaching pieces of lodestone to wooden splints floating on bowls of water. These splints always come to …

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