Question

How is an electromagnet different from a permanent magnet?
It has only south magnetic poles.
It has only north magnetic poles.
There is no magnetic field.
It can be turned on and off.

Answer 1

An electromagnet is different from a permanent magnet in that it can be turned on and off, whereas a permanent magnet always has a magnetic field. An electromagnet is created by passing an electric current through a coil of wire, which generates a magnetic field. The strength of the magnetic field can be controlled by adjusting the amount of current flowing through the coil. In contrast, a permanent magnet is made of a material that is naturally magnetic and always has a magnetic field, without the need for an external current.