Ultraviolet photons have more energy than visible photons. A single visible photon cannot excite the upper energy level needed to get ultraviolet light out.
At the very high intensities of some focused lasers, multiphoton absorption of visible light IS possible, with resulting ultraviolet emission, but it is not a common occurrence in nature.
They probably expect answer 2.
In the process of fluorescence, an atom ab-
sorbs a photon of ultraviolet light and emits
two or more photons of visible light.
Is the reverse process possible? (That is, is
it possible for an atom to absorb a photon of
visible light and emit photons of ultraviolet
light?)
1. Yes; ultraviolet photons have less energy
than visible light.
2. No; ultraviolet photons have more energy
than the visible light.
3. Yes; the energy is equal;
4. More information is needed.
5. None of these
1 answer
3 answers