Magnetic Fields

Magnetic fields are created when you have a moving charge like a bunch of similar spinning electrons in a permanent magnet or current running through an electromagnet.  Any magnet has a dipole, a north and south pole. Learn to draw and calculate magnetic fields using a few simple steps.

Drawing Magnetic Field Lines

  1. Magnetic field lines are drawn to represent the magnetic fields that would interact with a compass.
  2. Stronger magnetic fields are represented by more lines drawn.
  3. Arrows are drawn to represent a north to south direction vector.   The direction the north of a compass would face any position around the magnet.

Magnetic Fields Around a Bar Magnet

Here you see the magnetic field lines around a bar magnet.

Outside the magnet the greatest magnetic field is next to the poles.  You can see this in the density of field lines.  The field lines are more compact, closer together, around the poles.

Magnetic Field Lines Around A Bar Magnet

Magnetic Field Lines Around A Bar Magnet

North and South Pole Magnetic Field Lines

When a north pole of a magnet is next to a south pole the magnetic field you see an attraction in the field lines.  The lines are drawn from the north pole of one magnet to the south pole of the other.  The direction, as always for magnetic field lines, is away from the north toward the south.  The direction the north of a compass would point.

North to South Attractive Magnetic Field Lines

North to North Pole Magnetic Field Lines

When a north pole of a magnet is nest to another north pole you will see a repulsion in the field lines.  The direction of the field lines point away from the north pole and field lines from both north poles stay away from each other .

North to North Repulstive Magnetic Field Lines

North to North Repulsive Magnetic Field Lines

Magnetic Flux

Magnetic Flux is a measure of the number of magnetic field lines passing through a given point.  The more magnetic field lines the stronger the flux and interaction with other magnets and ferromagnetic materials.

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