Light is electromagnetic radiation, particularly radiation of a wavelength that's visible to the human eye (about 400–700 nm, or perhaps 380–750 nm). In physics, the term light sometimes refers to electromagnetic radiation of any wavelength, whether visible or not. Four primary properties of light are: Intensity Frequency or wavelength Polarization Phase Light, which exists in tiny "packets" called photons, exhibits properties of both waves and particles. This property is referred… (More on Light)