Question

What is the source of all electromagnetic waves?

Answer 1

Electromagnetic radiation, is a form of energy emitted by moving charged particles. As it travels through space it behaves like a wave, and has an oscillating electric field component and an oscillating magnetic field.
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Answer 2

The source of all electromagnetic waves are:

• All EM waves are generated by accelerated electrical charges; the energy source is whatever is accelerating.
• When an atom absorbs energy, it emits electromagnetic radiation.
• One or more electrons within the atom move as a result of the absorbed energy.
• Electromagnetic waves are made up of a sinusoidal change of the electric and magnetic fields that are at right angles to each other and the wave propagation direction.