What is electromagnetic radiation?

Answer:

Electromagnetic radiation, or EMR, is a term we apply to the phenomenon of the movement of electromagnetic (EM) energy through the propagation of a wave. This wave, which moves at the speed of light in a vacuum, is composed to two intertwined waves. (Light itself is an electromagnetic wave.) An electric and a magnetic wave that are in phase, but are perpendicular to each other, are self-propagating in this almost omnipresent, natural occurrence

The wave has the properties of frequency (and wavelength, which is the inverse of frequency), and amplitude. It is also polarized, meaning it has polarity, owing to the orientation of the two constituent waves about their path of travel. We know something about this phenomenon because we have experienced it all our lives, at least in its form as light. Electromagnetic radiation is also given other names, depending on its frequency.

The lowest frequency EM waves are radio waves, and they reach up into microwaves The microwaves, in turn, reach up into the far infrared (IR) band, then the near IR band. These are just below the optical frequencies, or the spectrum of visible light. We see red, orange, yellow, green, blue and violet in the color spectrum, and we know them well (save for those of us who are color blind). Above the violet and "out of sight" as it were are the ultraviolet (UV) frequencies. Then we'll see the X-rays and beyond them the gamma rays, which are the highest frequencies and the highest energy forms of EM radiation.

Across all of the spectrum, the electromagnetic spectrum, we'll grab a band of frequencies and generate the waves to use them for different things. You already know the benefits of radio waves and microwaves. And you've used the optical spectrum all your life. X-rays are something you know of as well. And the gamma rays, which are generated by changes in atomic nuclei, pass through you all the time because of natural radiation. There is more to learn, and links are provided below to get you further down the road.