David 07 May 2016 - 5


38. The figure below shows a permanent magnet suspended from a spring placed right on top of an electromagnet.

What will happen to the permanent magnet once the switch S is turned on?


When the switch is closed, current will flow in the direction as shown by the arrows on the wires in the diagram below. Based on the right hand-grip rule, the magnetic field produced by the current will be as shown below.

This means that the top of the iron core will be a magnetic North pole and repel the North pole of the permanent magnet. Hence, the permanent magnet will be pushed upwards.