Warmer objects emit more infrared radiation than cooler objects. Common uses for infrared radiation are night vision scopes, electronic detectors, sensors in satellites and airplanes, and in astronomy. Microwave wavelengths range from approximately one millimeter to about thirty centimeters or about one foot in length. The energy spectrum of microwaves has been utilized in oven technology where the wavelength is tuned to frequencies that are readily absorbed by water molecules in food causing them to absorb energy and release heat as they vibrate. Microwaves are the highest frequency radio waves and are emitted by the Earth, buildings, cars, planes, and other large objects.
Radio waves are well known for their ability to transmit radio and television signals.
This wide spectrum of electromagnetic radiation ranges from wavelengths of less than a centimeter to tens and even hundreds of meters. FM radio waves are shorter in length than AM waves and tend to be blocked by large objects such as houses, buildings, and tunnels. AM waves are longer than FM waves and can be bent around these large objects to improve reception. A majority of the frequencies are invisible to the human eye, but this radiation occurs everywhere and we are continually being bombarded by the entire frequency range of electromagnetic radiation. Authors Mortimer Abramowitz - Olympus America, Inc., Two Corporate Center Drive., Melville, New York, 11747.