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How do changing electric and magnetic fields form electromagnetic waves such as light and radio waves?

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Diagram showing a circular loop of wire with an electric current, surrounded by curved blue lines representing magnetic field lines that loop around the wire and pass through its center. — magnetism Some lines of the magnetic field B (blue) for an electric current I (gold) in a loop.

Electromagnetic waves, such as light and radio waves, are formed through the mutual interaction of changing electric and magnetic fields. This process is described by Maxwell’s equations, which unify electricity and magnetism into a single framework.123

The formation of these waves relies on two fundamental principles:
* Changing magnetic fields produce electric fields: This is a statement of Faraday’s law of magnetic induction.3
* Changing electric fields produce magnetic fields: Maxwell predicted this effect, identifying that a changing electric field acts as a source of a magnetic field, a concept he termed displacement current.3

In an electromagnetic field, a changing electric field continually gives rise to a changing magnetic field, and vice versa. These propagating oscillations in field strength travel through space as electromagnetic waves. In a vacuum, these waves propagate at the speed of light, with the electric and magnetic fields oscillating perpendicular to each other and to the direction of the wave's travel.243