The frequency and wavelength of EM waves can vary over a wide range of values. Scientists refer to the full range of frequencies that EM radiation can have as the electromagnetic spectrum. Electromagnetic waves are used extensively in modern technology. Many devices are built to emit and/or receive EM waves at a very specific frequency, or within a narrow band of frequencies. Here are some examples followed by their frequencies of operation:
garage door openers: 40.0 MHz,
standard cordless phones: 40.0 to 50.0 MHz,
baby monitors: 49.0 MHz,
FM radio stations: 88.0 to 108 MHz,
cell phones: 800 to 900 MHz,
Global Positioning System: 1227 to 1575 MHz,
microwave ovens: 2450 MHz,
wireless Internet technology: 2.4 to 2.6 GHz.