# Magnetic Lines of Force

### After completing this section you will be able to do the following:

• Explain how magnetic lines of force enter and exit a bar magnet.
• Discuss how magnetic lines of force act upon other ferromagnetic objects.

## Magnetic Lines of Force

The lines that we have mapped out around the magnet, called the magnetic lines of force, indicate the region in which the force of the magnet can be detected. This region is called the magnetic field.

If an iron object is near a magnet, but is not within the magnetic field, the object will not be attracted to the magnet. When the object enters the magnetic field, the force of the magnet acts, and the object is attracted. The pattern of these lines of force tells us something about the characteristics of the forces caused by the magnet. The magnetic lines of force, or flux, leave the north pole and enter the south pole.

## Earth as a Magnet

Since the earth is a huge magnet with a magnetic north and south pole, the lines of magnetic force around the earth look like there is a huge vertical bar magnet running through the center of the earth.

### Review:

1. The magnetic lines of force, indicate the region in which the force of the magnet can be detected. This region is called the magnetic field.
2. The magnetic lines of force, or flux, leave the north pole and enter the south pole.