Total range of frequencies or wavelengths of electromagnetic radiation. The spectrum ranges from waves of long wavelength (low frequency) to those of short wavelength (high frequency); it comprises, in order of increasing frequency (or decreasing wavelength): very-low-frequency to ultrahigh-frequency radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays, and gamma rays. In a vacuum, all waves of the electromagnetic spectrum travel at the same speed: 299,792,458 m/sec (186,282 mi/sec).
The spectrum of electromagnetic waves ranges from low-frequency radio waves to high-frequency gamma
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