Which dimension of color is determined by the wavelength of light?

The dimension of color determined by the wavelength of light is hue. Hue refers to the specific color attribute that allows us to distinguish between colors such as red, blue, green, and yellow. Each color corresponds to a different wavelength of light; for instance, shorter wavelengths are perceived as blue or violet, while longer wavelengths appear red.

Brightness relates to the perceived intensity of light, which can occur at any wavelength, while saturation refers to the purity of a color, indicating how much it is diluted with white light. Contrast deals with the differences between colors or shades in terms of their brightness and can influence perception but is not a dimension of color itself. Thus, hue is the correct answer since it directly correlates to the wavelength of light.