Final answer:
An electromagnet is a type of magnet that can be turned on and off with an electric current. It employs a ferromagnetic core to enhance its magnetic field, whose strength can surpass even the strongest permanent magnets and the Earth's own magnetic field.
Step-by-step explanation:
A electromagnet is a strong magnet that can be turned on and off. An electromagnet consists of loops of wire usually wrapped around a ferromagnetic core, which enhances the magnetic effects. When an electric current flows through the coils, it produces a magnetic field. This magnetic field is similar to that of a permanent magnet, with a north and a south pole. However, unlike a permanent magnet, the magnetic field generated by an electromagnet can be controlled by starting or stopping the electric current, making it very versatile in its applications, such as in motors and lifting machinery.
Utilizing materials like iron, cobalt, and nickel, electromagnets can create very strong magnetic fields. These materials are ferromagnetic and can retain their magnetic behavior even when exposed to demagnetizing influences. Electromagnets can also be incredibly strong, with fields much more robust than the Earth's magnetic field, as demonstrated by superconducting electromagnets which may attain fields of 10 T (tesla) or more.