Electromagnetic radiation and electromagnetic waves are closely related but have slight differences in their terminology and context.
Electromagnetic radiation refers to the energy that is propagated through space or a medium in the form of electromagnetic waves. It encompasses the entire electromagnetic spectrum, which includes various types of waves such as radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays, and gamma rays. Electromagnetic radiation carries energy and momentum and can interact with matter.
On the other hand, electromagnetic waves specifically refer to the oscillating electric and magnetic fields that propagate through space or a medium. These waves are a manifestation of electromagnetic radiation. They are characterized by their wavelength, frequency, and amplitude. Electromagnetic waves can be described as the self-propagating disturbance of electric and magnetic fields that are perpendicular to each other and to the direction of wave propagation.
In terms of conversion, it is not possible to convert one directly into the other because electromagnetic radiation refers to the energy itself, while electromagnetic waves describe the oscillating fields that carry that energy. However, electromagnetic radiation can be generated or detected through the production or reception of electromagnetic waves.
For example, when an antenna generates an oscillating electric current, it produces electromagnetic waves in the form of radio waves. These waves propagate through space as electromagnetic radiation. Similarly, when electromagnetic waves such as visible light strike the retina of the eye, they are detected, leading to the perception of light.
So, while electromagnetic waves are the physical phenomenon that propagates, electromagnetic radiation is the broader term that encompasses all forms of electromagnetic waves and their associated energy.