The aspect of light that determines its color is its wavelength. Different wavelengths of light correspond to different colors within the visible spectrum. For example, shorter wavelengths appear blue, while longer wavelengths appear red. The visible spectrum ranges from approximately 380 nm (violet) to about 750 nm (red). When light interacts with objects, its wavelengths can be absorbed, reflected, or refracted, influencing the color we perceive. Understanding light's wavelengths is fundamental in fields like optics and photography.