Magnetic Fields and Electromagnetic Waves

Abstract

Almost everyone has performed elementary experiments with bar magnets. If the bar magnet is suspended by a thread or supported by a pivot, one of the ends will point in a northerly direction. This end of the magnet is called the north pole of the magnet, with symbol N. The opposite end of the magnet is called the south pole, with symbol S. Elementary experiments also show that like poles repel and unlike poles attract. This suggests that there is something that we call a magnetic field by which poles can exert forces on each other. This field is similar to the two other fields we have already considered, the gravitational field and the electric field. There is one important difference, however: If we break a bar magnet in half, we cannot make single poles, but instead we will have two bar magnets. The broken end becomes the south pole of the half that has the north pole, and the other broken end becomes the north pole of the half that has the south pole.