Force in a third direction(Teaching tip)



Keeping the three directions in mind: current; field; force

Hans Christian Ørsted (1777–1851) was a Danish physicist and chemist who is most widely known for observing that electric currents produce a magnetic field. In the case of a straight conducting wire, the magnetic field lines are circular in shape, centred on the line of the wire.

When a current-carrying wire is placed in the space between two attracting magnets a force acts on the current-carrying wire. This is perhaps not surprising since the current-carrying wire is a magnet and it therefore experiences a force when placed in a magnetic field. What is surprising is the direction of the force on the wire.

The force on the current carrying wire:

  • Is not in the direction of the current in the wire.
  • Is not in the direction of the magnetic field between the attracting magnets.
  • Is in a third direction: at right-angles to both the wire and the field.


  • Prepare for teaching across the topic using these links

    topic kitset topic path core ideas (topic) decisions to make (topic) suggestions (for the topic) topic issues



    This is a nugget in the TL thread – connect all three threads from any link

    Physics Narrative (PN) Teaching & Learning Issues(TL) Teaching Approaches(TA)

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