Light is electromagnetic radiation, particularly radiation of a wavelength that is visible to the human eye (about 400–700 nm, or perhaps 380–750 nm). In physics, the term lightsometimes refers to electromagnetic radiation of any wavelength, whether visible or not.

This are the spectrum of lights

The speed of light in a vacuum is presently defined to be exactly 299,792,458 m/s. Just say 3x10^8 m/s.

Lambda (λ) is the 11th letter of the Greek alphabet.

This picture consist of 2.5 waves or 2.5 lambda. 1 lambda is a path that is traveled for 360 degrees

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