What is the electromagnetic spectrum?
The electromagnetic spectrum is a vast band of energy frequencies extending from radio waves to gamma waves, from the very lowest frequencies to the highest possible frequencies. The spectrum is arranged by the frequency of its waves, from the longest, lowest energy waves to the shortest, highest energy waves. Our ability to tune in the more exotic electromagnetic waves has grown in recent decades. For instance, radio is part of the spectrum, and it was only in the 20th Century that humans began to be able to use any of the electromagnetic spectrum, starting with radio at the long-wave end of the spectrum. Today, living and working in the 21st century, we make great use of the electromagnetic spectrum in all of our vocations and avocations. All of the frequencies we use for transmitting and receiving energy are part of the electromagnetic spectrum. For instance: • RADIO. We use the radio portion of the electromagnetic spectrum for many things, including television and radio broadcastin
“Electromagnetic radiation is categorized by wavelength or frequency.” We know that infrared radiation is a form of electromagnetic radiation, which is longer in wavelength than visible light. Other types of electromagnetic radiation include x-rays, ultraviolet rays, radio waves, etc. Electromagnetic radiation is categorized by wavelength or frequency. Broadcast radio stations are identified by their frequency, usually in kilohertz (kHz) or megahertz (MHz). Other spectrums are categorized by their wavelength. The unit of measurement used is the micrometer, or micron, (m) which is one millionth of a meter. The visible part of the electromagnetic spectrum falls between 0.4 and 0.75 micrometers. We can see colors because we can discriminate between different wavelengths. The infrared cameras detect radiation in the 8 to 12 micrometer band we usually call “longwave” or between 3 to 5 micrometers and is termed “shortwave.” Most commercial infrared detectors today use the longwave spectrum.
