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When you finish this page, go to the Light Quiz.

Light is one of our most common words - we speak of seeing light, how things light up,etc.. But how do scientists define light?

Light is electromagnetic radiation of a wavelengths. They all consist of electrical and magnetic fields that work together in a special way to form electromagnetic radiation. For humans to see this wavelength it must be from around 4,000 (violet) to about 7,700 (red) angstroms. The term lightis often extended to wavelength ranges that the eye cannot detect - to infrared radiation, which has a frequency less than that of visible light, and to ultraviolet radiation and black light, which have a frequency greater than that of visible light.

The study of light's behavior is called optics. The speed of light is 299,792,458 meters per second, or about 186,282 miles per second (299,792 kilometers per second).

What is electromagnetic radiation? It could be defined as energy emitted in the form of a wave as a result of the movement of electric charges. A moving charge creates a magnetic field. If the motion is changing , then the magnetic field changes. This then makes an electric field. Unlike sound waves, electromagnetic waves do not require matter to move.

The different types of electromagnetic radiation include electric waves, radio waves (including AM, FM, TV, and shortwaves), microwaves, infrared radiation, visible light, ultraviolet radiation, X rays, and gamma radiation.


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