Question

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?

Answer

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.