Ok, i know that colour percieved is due to the wavelength of light emitted by a substance/body, or the combination of different wavelengths.
But what causes bodies to emit these particular wavelengths?
IIRC from high school physics, a photon is emitted when an electron changes orbit in an atom… but wouldn’t the energy of the electron (and hence photon) be different depending on which orbit the electron was in?
Why, for instance, does iodine look consistantly purple? And how come it can sometimes be yellow?
Can anyone explain to me why things are the particular colour they are on a more fundamental level than “duh, because that’s the wavelength of light they emit/reflect”?
Oh yeah, why does reflected light reflect as a specific colour wavelength from different atoms? Is it something to do with electron valence arrangements?
An object can appear differently coloured depending on the light source with which it is illuminated, so I think the more relevant consideration is what wavelengths of light are not absorbed.
Sorry, I should have added that presumably, the non-reflected radiation corresponds to a specific electronic transition according to E=hv, although I’m a little concerened that this seems too simplistic. I’m sure someone will be along soon to either do a thorough search or give a better answer.
An ordinary substance at reasonable temperatures is usually in its “ground state”, which means that all electrons are in their lowest energy configuration. If you put a substance into an excited state (usually by heating it), then its spectral response will, in fact, change, so it may appear to be a different color. This isn’t very important for day-to-day matters on the Earth, but it’s a very valuable tool in astronomy for determining the temperature of objects you’re looking at.