[lightarrow]

Yes, if the electrons move not with pure sinusoidal motion, but with a composite motion then of course they'll emit (or reflect) multiple wavelength photons simultanously (on a classical scale, at least).

Ok with the multiple wavelength simultanously; but this doesn't necessarily mean "multiple photons of different wavelength simultanously". The reason is that a photon can have a spectrum of different wavelengths; actually, it's very unprobable that a real photon has an exact wavelength. In general it is in a superposition of different states of exact wavelength each.

From the Heisenberg relation >~1 where is the frequency, you can deduce the minimum value of for a single photon emitted by an atom in the time .
Example: an electron in an atom decays from an excited to the fundamental level tipically in 10^-8 s. It means that photon has a spectrum with > 10⁸ Hz.

Lasers generats much more monochromatic photons because the excited levels (called "metastable") decays in a much longer time.

[scientist]

Lightarrow has explained very well(for me, obviously)...
I haven't completely understood what you all have said but still it has cleared my doubts at some extents.

I want to raise another question... new thread continued at How can transparent glass act like a mirror? ...mod