Reference: EM149
Category: Electromagnetism
Purpose: Shows the magnetic field due to a current-carrying wire.
Description: a) A vertical wire passes through a glass plate mounted on a wooden stand. A number of very small compass needles are placed around it on the glass. Pass current from the variable power supply in the first year lab. (There are two of these demonstrations. One has a six volt battery pack attached, but the batteries may need to be replaced.)
b) A single layer, rather openly wound, solenoid is mounted on (actually, is bisected by) a Perspex plate. Pass current from the variable power supply in the first year lab after placing a number of small magnets inside and around the solenoid.
Show the effect of reversing current in both cases.
