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Is it fair to say the following?

"When light shines on an object, say a green leaf, it excites electrons on the atoms of the leaf to go to higher energy levels. As the electrons fall back to lower energy levels, the atoms of the leaf emit photons with the energy E = hv where h is Planck's constant and v is the frequency of the emitted photon. The dominant wavelengths of these photons correspond to the color green in the visible light spectrum."

If the above is true, then why do we say that leaves are green because it reflects green light and absorbs everything else? Isn't it more accurate to say that leaves absorb green light? Also, if I took a leaf to a room with only red light, why does the leaf look red rather than black?

Along the same lines, is it true that electrons can only absorb photons with the exact energy needed to move electrons from one energy level to another (as in atomic absorption spectroscopy)?

[DevaDevil]

Along the same lines, is it true that electrons can only absorb photons with the exact energy needed to move electrons from one energy level to another (as in atomic absorption spectroscopy)?

no, all photons with higher energy than the gap can be absorbed to higher energy levels. The electrons will quickly decay to the lowest excited state without emitting visible light, and the final decay emits a photon with the wavelength of the color you identify the object with.


this leads me to:

If the above is true, then why do we say that leaves are green because it reflects green light and absorbs everything else?

it "reflects" only because it re-emits the green photon from the electron decay from the excited state; therefore you could also say it emits green light.


finally:

Also, if I took a leaf to a room with only red light, why does the leaf look red rather than black?

In red light, the leaf does not absorb photons as their energy is lower than the energy required to reach excited states.