Physlet Illustration: Magnetic Field of a Bar Magnet

 

 

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In this simulation, a bar magnet is shown. A compass (whose needle points "north") may be dragged around in the plane of the screen. Can you map the lines of the magnetic field due to the magnet?

Hints:

  1. Like magnetic poles repel and unlike poles attract.
  2. The arrow end on the compass needle is a "north seeking" (or simply a "north") pole.
  3. Magnetic field lines begin on north poles and end on south poles and show, at any point along the line, the direction of the force that would be experienced by a north pole.
  4. What, then, is the connection between the compass and the field lines?
  5. What are the shapes of the field lines in the vicinity of the magnet?
  6. Can you determine which end of the magnet is a north pole?

Reference

See Walker, Section 22-1

Illustration written by Steve Mellema