Which term describes the proportion of incident light reflected by a surface?

Which term describes the proportion of incident light reflected by a surface?

• A. Albedo
• B. Reflectivity
• C. Absorptivity
• D. Transmittance

Answer: (A)

Albedo is the fraction of incoming light that a surface reflects. It’s defined as the ratio of reflected radiant flux to the total incident radiant flux, so it describes how reflective a surface is. This value ranges from 0 (no reflection, all light absorbed) to 1 (all light reflected). It can vary with wavelength and geometry, which is why planetary and climate studies talk about the albedo of a planet or ice compared with the color of a material in graphics. The other terms describe other parts of what happens to light: absorptivity is what gets absorbed, and transmittance is what passes through. In many contexts, reflectivity and albedo are used similarly, but the precise descriptor for the portion of light reflected by a surface is albedo.

Albedo is the fraction of incoming light that a surface reflects. It’s defined as the ratio of reflected radiant flux to the total incident radiant flux, so it describes how reflective a surface is. This value ranges from 0 (no reflection, all light absorbed) to 1 (all light reflected). It can vary with wavelength and geometry, which is why planetary and climate studies talk about the albedo of a planet or ice compared with the color of a material in graphics. The other terms describe other parts of what happens to light: absorptivity is what gets absorbed, and transmittance is what passes through. In many contexts, reflectivity and albedo are used similarly, but the precise descriptor for the portion of light reflected by a surface is albedo.