Kelvin (K): The approved unit of measure in the metric system, one Kelvin is equal to one degree Celcius; however, the Kelvin scale is referenced to absolute zero temperature, rather than the freezing point of water. Note that the term (or symbol) ‘degree’ is not used with Kelvin (i.e., 273 K = 0oC).
Kirchoff’s Law: A thermodynamic relationship that governs some aspects of radiation heat transfer. A form of Kirchoff’s Law that is relevant to practical thermal imaging applications is that the emittance of an object is equal to the absorptance of that object, if the object is at a constant temperature, and over the same spectral (wavelength) range.
