Physlet Illustration: Magnetic Field of a Solenoid

 

 

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In this simulation, a solenoid is oriented perpendicular to the plane of the screen. It carries a current that runs into and out of the screen. 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 caused by the solenoid?

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 solenoid? Inside the solenoid?
  6. Can you determine in which part of the solenoid current flows into the screen and where it flows out? (Remember the right-hand rule.)

Reference

See Walker, Section 22-6

Illustration written by Steve Mellema