Biology 1002B Chapter Notes - Chapter lecture 2: Electromagnetic Spectrum, Photon, Conjugated System
19 Dec 2017
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Characteristics of the electromagnetic spectrum: the range of wavelengths or frequencies of electromagnetic radiation extending from gamma rays to the longest radio waves and including visible light. Definition of light: light serves two important functions for life on earth. First, it is a source of energy that directly or indirectly sustains virtually all organisms. Second, light provides organisms with information about the physical world that surrounds them: light is most commonly defined as the portion of the electromagnetic spectrum that humans can detect with their eyes. This is a very narrow portion of the total electromagnetic spectrum, only spanning the wavelengths from about 400 to 700 nm. In physics, the definition of light often includes other regions of the electromagnetic spectrum, and thus terms such as visible light, ultraviolet light, and infrared light are commonly used: light is best understood as a wave of photons.
