Question

How are an electromagnet and a permanent magnet different from one another?

Responses

The strength of an electromagnet can be varied because its strength depends on the number of turns of conducting wire around a plastic core.
The strength of an electromagnet can be varied because its strength depends on the number of turns of conducting wire around a plastic core.

The strength of a permanent magnet is always greater than an electromagnet because it has two separate poles.
The strength of a permanent magnet is always greater than an electromagnet because it has two separate poles.

The strength of a permanent magnet is always greater than an electromagnet because it can create an electric current in the absence of a wire.
The strength of a permanent magnet is always greater than an electromagnet because it can create an electric current in the absence of a wire.

The strength of an electromagnet can be varied because the magnetic field depends on the flow of an electric current through the wire.

Answer 1

The strength of a permanent magnet cannot be easily changed because the alignment of its magnetic domains is fixed.