How is electromagnetic energy measured?
Electromagnetic energy is measured in units of wavelength and frequency. The wavelength is the distance that a wave travels in one cycle and is measured in metres. The frequency is measured by the number of cycles per second and the unit of measurement is the Hertz (Hz). One cycle per second equals one Hertz. One kilohertz (kHz) is 1,000 Hz; one megahertz (MHz) is one million Hz; one gigahertz is one billion Hz. The frequency of a wave is inversely related to its length – at 50 Hz the wavelengths are 6,000 Km, and at 100 MHz they are 3 metres. Electromagnetic fields are arranged according to their frequencies in an orderly fashion in what is known as the electromagnetic spectrum.
