Light through glass ?

  • Thread starter cragar
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  • #1
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Main Question or Discussion Point

If atoms can only emit certain photons , like hydrogen has only certain spectral lines in the visible spectrum , then how come when i shine pretty much any color of light through glass
it hits the atoms in the glass and then re-emits them , what are the spectral lines for glass
(silicon dioxide) , it certainly would not be a continuous spectrum , so why can white light go through glass and come out if it contains all colors of light .? Wouldn’t some of these colors be in-between the band gap , and I might get a different color out then what I shined into the glass , is this what dictates whether a material is transparent or not.
 

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  • #2
mgb_phys
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If atoms can only emit certain photons , like hydrogen has only certain spectral lines in the visible spectrum
So it only absorbs certain lines, which is why you can see through most gases.

t hits the atoms in the glass and then re-emits them , what are the spectral lines for glass (silicon dioxide)
That's the difference, the light hits atoms is absorbed and remitted (actually it's absorbed by bonds between atoms), the lines in the visible band are caused by photons absorbed by electrons and there aren't any electrons in glass at the right wavelengths.
Higher energy UV photons can be absorbed by electrons, longer wavelength infrared photons can be absorbed by the si-o bonds (and any H-O from traces of water)
 
  • #3
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so the bonds in the glass are responsible for the light that i see , not the individual electrons , is this the same for light coming through our atmosphere .
 

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