Electromagnetic waves are classified based on their wavelength (you can Google this and find charts that provide this information).
If an E.M. wave has a wavelength of 1012 meters (that is, its wavelength is greater than 1000 meters, or a kilometer, km) then it would be classified as Low Frequency (LF). These have a frequency of 30-300 kHz and a wavelength of from 1 to 10 km
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