What is an electromagnet?

An electromagnet is defined as a magnet whose magnetic field is produced by an electric current. When electric current flows through a coil of wire, it generates a magnetic field around the coil. The strength of this magnetic field can be controlled by adjusting the current flowing through the wire. This ability to turn the magnetic field on and off, as well as to vary its strength, makes electromagnets particularly useful in various applications, such as in electric motors, transformers, and magnetic locks.

The other options describe different types of magnets that do not depict the characteristics of electromagnets. For instance, a permanently magnetized magnet does not rely on an electric current, whereas a magnet that cannot be turned off suggests a fixed magnetic field, which is not true for electromagnets that can be toggled by controlling the current. Lastly, natural occurring magnets refer to minerals like magnetite that possess inherent magnetic properties without the need for an electric current.