Radiation, Reflection, and Emission of Electromagnetic Energy
- When radiation interacts with matter it can be detected in a variety of ways depending upon the frequency of the energy reflected. Reflected energy is detected as light waves, emitted energy is detected as heat.
- Incident angle, wavelength of incident reflection, and properties of the target material (land, water, heat, etc.) determine how the matter interacts.
- Matter warmer than 0 K (-273.15 degrees celsius) emits electromagnetic energy--the higher the temperature, more energy is emitted.
- An 'ideal black body' is a theoretic model that absorbs ALL energy falling upon it and can later emit all energy.
- An 'ideal reflector body' is a theoretic model that reflects ALL energy incident to it, neither absorbing nor emitting any energy.
- Neither of these 'ideal bodies' exist in natural material on Earth. These models are used as a frame of reference only.
- Emissivity = amount of energy emitted from a material divided by the amount of energy emitted by an ideal black body.
