Some background first
Plancks law vs Maxwell's theory:
Planck : states that 1. energy is emitted and absorbed in discrete quanta (photons), and 2. The energy in each quantum is hv. (E=hv) where h = plancks constant 1.626*10 to the -34 J * second. V= frequency in hertz.
Maxwell is the electromagnetic theory, 1. luminous bodies emit light in the form of radiant energy 2. radiant energy is propagated in the form of electromagnetic waves and 3. electromagnetic waves act on the retina of the human eye.
Plancks law vs Maxwells theory are the basis for any theoretical explaination of light and it's behaviour as it relates to light source choice, chromatic, monochromatic etc. I cannot remember all the multiple guess parts of the question, but that was the gist of it.
In regards, to a blackbody: it's a theoretical light source that absorbs all the radiant eergy that falls upon it and is a uniform temperature radiator. In other words, at any given temperature, the black body radiates more power at any wavelength than any other object at the same temperature.
The black body and color temperature are related in theory. The spectral emissivity of a light source is the ratio of light output vs the theoretical output of a blackbody.
The color temperature of a light source is determined by the temp at which a blackbody must operate in order to produce an emissivity that most closely matcheds the emissivity of a light source.
Thats the theory, now I know for an imaging device, the color of that light must be known for accurate representation of the image being recorded, and the color temperature from a given source as mentioned above is related to this. It's typically given in degrees kelvin. (example, candle flame, 2000, tungsten halogen lamp 3500, Photographic daylight between 5k and 6k.).
So as an answer to your question, all roads lead to rome as the three questions where inter related. Which is How I answered them, I found the ones that jived with each other.
regards,
gerald