# The poles of the magnet

How to determine the poles of the magnet? This question is not as simple as it seems at first glance. After all, we have no confidence that the magnet poles are not painted in different colors just to distinguish them. In addition, the magnet can not be labeled at all.

For the experiment, you need to constantly horseshoe magnet... and old unwanted TV. Experience is best done in the morning or in the afternoon, when some TV channel is transmitted to the grid settings TVs.

Bring a magnet pole of some kind to the screen on the TV. Picture distorted immediately. The central part of the grid is displaced upwards or downwards, depending on how the disposed magnet poles.

The image on the TV screen creates an electron beam coming from the bottom of the tube. Our magnet deflects the moving electrons, so the image is shifted. The direction of the magnetic field acts on a moving charge is determined by the left-hand rule. It is necessary to position the hand so that the lines of force are included in it, and elongated fingers pointing direction of the current. Then, bent at a right angle of the thumb indicates the direction of displacement of the moving charge. Power lines go from the north to the south pole of the magnet. The current direction in the left-hand rule is considered to be from plus to minus. But CRT move electrons that fly at us. This is equivalent to the positive charges are flying away from us. Therefore outstretched fingers of the left hand should be directed to the screen. The rest becomes clear. By displacement of the central part of the grid television determine which pole of the magnet holding to the screen, north or south.

So, with the help of TV, you can easily and quickly determine the poles of a magnet.