How is electromagnetic induction used in induction stovetops?

Induction stovetops use electromagnetic induction to generate heat directly in the cookware, without heating the stovetop itself.

Electromagnetic induction is a fundamental principle in physics, discovered by Michael Faraday in 1831. It describes the process by which an electric current is generated in a conductor when it is exposed to a changing magnetic field. In the case of induction stovetops, the conductor is the cookware and the changing magnetic field is created by a coil of wire beneath the stovetop surface.

When the stovetop is switched on, an alternating current flows through the coil, creating a dynamic magnetic field. This magnetic field induces an electric current in the cookware placed on the stovetop. The resistance of the cookware to this induced current generates heat, which is then transferred to the food being cooked. This is known as Joule heating or resistive heating.

The key to this process is that the cookware must be made of a ferromagnetic material, such as iron or stainless steel. These materials have a high magnetic permeability, which means they can easily be magnetised and demagnetised by the changing magnetic field. Non-magnetic materials like glass or aluminium do not work on induction stovetops because they cannot generate sufficient heat through electromagnetic induction.

One of the main advantages of induction stovetops is their efficiency. Because the heat is generated directly in the cookware, rather than being transferred from the stovetop, less energy is wasted. This makes induction stovetops more energy-efficient and faster at heating up than traditional gas or electric stovetops. Furthermore, because the stovetop itself does not get hot, it is safer and easier to clean.

In summary, induction stovetops utilise the principle of electromagnetic induction to generate heat directly in the cookware. This is achieved by creating a changing magnetic field with an electric coil, which induces an electric current in the cookware. The resistance of the cookware to this current generates heat, which is used to cook the food.