Reference: EM151
Category: Electromagnetism
Purpose: Shows the direction of the magnetic field around a current-carrying wire.
Description: A long horizontal wire is mounted on a wooden stand. Current is supplies by a 12V battery through a switch and a rheostat. Set the wire magnetic North-South. Stand two pivoted compass needles (not too near each other) so that one is just above the wire, the other below. Show that they deflect in opposite directions, and that the deflection increases with increasing current.
