The Hue of a colour is related to its : 

The correct answer is Wavelength

Key Points

• Wavelength:
  • This is the distance between two successive crests or troughs in a wave— in this context, a light wave.
  • The wavelength of light determines its color, or hue. Different colors of light have different wavelengths.
  • For instance, violet light has a short wavelength, while red light has a long wavelength. So this is the term most closely connected with the hue of a color.

Additional Information

• Luminance:
  • This is a photometric measure of the luminous intensity per unit area of light traveling in a given direction.
  • It describes the amount of light that passes through or is emitted from a particular area, and falls within a given solid angle. It's often used in the context of the emission or reflection of light from flat, diffused surfaces.
• Saturation:
  • In color theory, saturation refers to the intensity of a color. It's the degree to which a color is different from a gray of the same brightness or lightness.
  • A highly saturated color is vivid, while an unsaturated color appears washed out or muted. 
• Incandescence:
  • This is the emission of light from a hot body as a result of its temperature. The color of incandescent light varies with the temperature of the light-emitting body.
  • This term is often used to describe the light emitted by traditional light bulbs, which work by heating a filament until it glows. Incandescence mainly connects to temperature.