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| Magnetization |
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 Single touch method |
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| Place the soft iron piece AB flat on a table and stroke it with a bar magnet from A to B with one end of a bar magnet as shown in figure. When the magnet reaches B it is lifted, and brought back to A to repeat the stroke. After a few strokes you will notice that A will possess the same polarity as the pole being rubbed with it. |
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Double touch method |
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| It was found that using two bar magnets we could magnetize a steel bar more uniformly. |
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| Place the steel bar flat on the table top, and place the opposite poles of two strong bar magnets inclined as shown. The magnets are moved apart and the stroke repeated from the centre. B will get south polarity and A will get north polarity after
magnetization. |
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By
passing electric current |
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| The best method of making a powerful magnet is
by passing electric current. Wind a length of an insulated copper wire around a steel rod DY and connect it to a battery and a switch. |
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| After the current has passed through the coil for some time you will notice that the steel rod gets
magnetized. The polarity of the rod depends upon the direction of the current. If the bar is viewed from one end and the current is found to be flowing in a clockwise direction, then that end will become a south pole and if the current is flowing in the anticlockwise direction then that end will be a north pole. |
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