12.1.A—Describe the properties of a magnetic field

Describe the properties of a magnetic field.

• A magnetic field is a vector field that can be used to determine the magnetic force exerted on moving electric charges, electric currents, or magnetic materials.
  • i. Magnetic fields can be produced by magnetic dipoles or combinations of dipoles, but never by monopoles.
  • ii. Magnetic dipoles have north and south polarity.
• A magnetic field is a vector quantity and can be represented using vector field maps.
• Magnetic field lines must form closed loops, as described by Gauss’s law for magnetism.
  • i. Maxwell’s equations are the collection of equations that fully describe electromagnetism. Gauss’s law for magnetism is Maxwell’s second equation. Relevant equation:
  • ii. Magnetic fields in a bar magnet form closed loops, with the external magnetic field pointing away from one end (defined as the north pole) and returning to the other end (defined as the south pole).