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When you look at absortion lines of light...

  1. Jan 14, 2016 #1
    in the absorption and emissions spectrum of elements, what happens to the light that is not absorb?

    -ed.
    in the absortion and emission spectrum of elements, in carbon there is a lot of colored light that carbon does not absorb.
    Like carbon absorbs blue light, but not all wavelengths of blue light.
    So what happens to all this colored light that does not get absorbed by carbon.
    Say in a four inch cubed block of carbon what is happening to the colored light thats not being absorbed, and emissioned by the carbon electrons, some of the colors of light have to be getting transmission through the four inch block of carbon.
    Whats really happening.
    Thank you for you help with this question, anything helps even a few words.
     
  2. jcsd
  3. Jan 14, 2016 #2

    DaveC426913

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    I'm no expert but usually absorption and emission spectra are separate.

    When carbon absorbs some blue light, what does not get absorbed reaches your detector.
    If carbon emits blue light, then that light is what reaches your detector.
    absemm.jpg

    I don't know about examining light that is first absorbed then emitted.
     
  4. Jan 14, 2016 #3
    Carbon isn't special in this sense , all elements absorb or emit EM at certain wavelengths.
    A low frequency form of EM, say radio frequency, would not be absorbed (much) by a four inch block of carbon.
    X-rays would be though. The carbon will get hot.
     
  5. Jan 15, 2016 #4
    when you meant detector did you mean, some of the light blue, light that carbon does not absorb, would get transmission through the carbon, and be detectable on the other side.
    Glassy_carbon_and_a_1cm3_graphite_cube_HP68-79.jpg
     
  6. Jan 15, 2016 #5

    DrClaude

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    A solid does not behave like a collection of individual atoms. The absorption spectrum of a bloc of carbon has nothing to do with the atomic spectrum of carbon. Case in point: do diamond and graphite have the same color?
     
  7. Jan 15, 2016 #6
    So the absortion, and emission spectrum in this diagram is for carbon gas, and not carbon solid.

    .https://mail.google.com/mail/u/0/?ui=2&ik=1a702d60a0&view=fimg&th=152423f8a01db4f4&attid=0.1&disp=emb&realattid=73f0543dd772c52d_0.1&attbid=ANGjdJ9q09cDCkalqGztvo2O9NW7YSxShK7zdZsbTlFAEs1qToCzxd-S9r_jPJ1e239hldvDmzPzUyzHx8R1xnuhsodAFXWCDDyNseVPV_wroPMKiHBd0ajUZHHGsxs&sz=w496-h406&ats=1452897686667&rm=152423f8a01db4f4&zw&atsh=1
    Maybe this diagram above was the absorption, and emission spectrum for carbon gas, so here in the diagram below is a diagram for the emission of iron, hopefully solid iron because it takes a lot of energy to turn iron to a gas.
    If you notice there is a large gap in the blue, and red emission chart for iron, (hopefully solid iron).
    So does this mean *some* of that wavelength of blue, and red light does get transmission through a four inch solid cubed piece of iron.
    So all this blue, and red colored light has to do is pass through four inches of solid iron, the blue, and red light does not need to pass through any more thicker iron material more than four inches.
    https://mail.google.com/mail/u/0/?ui=2&ik=1a702d60a0&view=fimg&th=15247719d336dd43&attid=0.1&disp=emb&realattid=ii_1524759e5a833243&attbid=ANGjdJ-mKebm2LDhl5c3tLdKMu6gDJ88PeuRfZHPDH92xitV0pQWB__mhZ_kaG5kUgu-fjL8IHEKDNaiDDSmAvbzhcq84evYloSDoB1NwIqm3fPupnNn9nSgiYwUYsI&sz=w1000-h392&ats=1452897686754&rm=15247719d336dd43&zw&atsh=1
    Thank you for your help Dr Claude.
     
    Last edited: Jan 15, 2016
  8. Jan 15, 2016 #7

    DaveC426913

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    Nicholas: we are not seeing any of your images. The URLs you are suing appear to be a PHP proxy to images. You need to provide the URL to the actual images.
     
  9. Jan 15, 2016 #8
    Okay, sorry here you go here the link,
    http://astrobob.areavoices.com/2010/03/25/how-we-wondered-what-you-were-and-now-we-know/
    Its the fourth image from the top.
    Spectra_emission_hydrogen_andiron.jpg
    The fingerprints of hydrogen (top) and iron when they emit light after being energized by heating. Iron has many more lines because it’s a much more complicated element than hydrogen with 26 protons and 26 electrons compared to hydrogen’s one proton and one electron.
     
  10. Jan 15, 2016 #9
    Also how come I can see the images.
     
  11. Jan 15, 2016 #10

    DaveC426913

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    OK, I'm seeing this one.
     
  12. Jan 15, 2016 #11
    Thank you so much for your answer, just 2 follow up questions.
    Maybe that was the absorption, and emission spectrum for carbon gas, so here in the diagram below is a diagram for the emission of iron, hopefully solid iron because it takes a lot of energy to turn iron to a gas.
    If you notice there is a large gap in the blue, and red emission chart for iron, (hopefully solid iron).
    So does this mean *some* of that wavelength of blue, and red light does get transmission through a four inch solid cubed piece of iron.
    So all this blue, and red colored light has to do is pass through four inches of solid iron, the blue, and red light does not need to pass through any more thicker iron material more than four inches.
    https://mail.google.com/mail/u/0/?ui=2&ik=1a702d60a0&view=fimg&th=15247719d336dd43&attid=0.1&disp=emb&realattid=ii_1524759e5a833243&attbid=ANGjdJ9BDdHe7XaRL2kFnoX2tFxFNXO_rAXzwllJA_lPB-bGVPfQp4yz8I_Cd4mD3LkDkPJk0_kaB4Ul9dDDvNDqbK63hwYf9m03drNwwKIpcaapbfsOVXFFJ_f5HkQ&sz=w1000-h392&ats=1452898970312&rm=15247719d336dd43&zw&atsh=1
    2. So you said "a solid black object would absorb all visible wavelengths", so there would be no emission lines on a chart for a solid black object, because solid black absorbs all wavelengths of light is this correct?
    Thank you very much for your help.
     
  13. Jan 15, 2016 #12

    mfb

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    You are logged in with your account at google. We are not.
    All those absorption lines are for gases, including iron. It takes a lot of energy to turn it into a gas, but it takes even more energy to excite those lines.

    Solid iron, as a metal, will reflect most visible light and absorb the rest. No transmission if your sample is thicker than a few ten micrometers.
    The opposite: the absorption plot would be completely black (as everything is absorbed), the emission part would be completely full with colors (as everything is emitted if the material is hot enough).


    From this thread:
    No transmission, just some reflection at the surface. Everything that is not reflected gets absorbed.
     
  14. Jan 15, 2016 #13
    Great, thank you for you answer that explains it all thank you.
     
  15. Jan 15, 2016 #14
    To move from a lower to a higher energy level, an electron must gain energy. Oppositely, to move from a higher to a lower energy level, an electron must give up energy. In either case, the electron can only gain or release energy in discrete bundles.

    Now let's consider a photon moving toward and interacting with a solid substance. One of three things can happen:

    1. The substance absorbs the photon. This occurs when the photon gives up its energy to an electron located in the material. Armed with this extra energy, the electron is able to move to a higher energy level, while the photon disappears.
    2. The substance reflects the photon. To do this, the photon gives up its energy to the material, but a photon of identical energy is emitted.
    3. The substance allows the photon to pass through unchanged. Known as transmission, this happens because the photon doesn't interact with any electron and continues its journey until it interacts with another object.
    Glass, of course, falls into this last category. Photons pass through the material because they don't have sufficient energy to excite a glass electron to a higher energy level. Physicists sometimes talk about this in terms of band theory, which says energy levels exist together in regions known as energy bands. In between these bands are regions, known as band gaps, where energy levels for electrons don't exist at all.

    Some materials have larger band gaps than others.

    Glass is one of those materials, which means its electrons require much more energy before they can skip from one energy band to another and back again. Photons of visible light -- light with wavelengths of 400 to 700 nanometers, corresponding to the colors violet, indigo, blue, green, yellow, orange and red -- simply don't have enough energy to cause this skipping.

    Consequently, photons of visible light travel through glass instead of being absorbed or reflected, making glass transparent.

    At wavelengths smaller than visible light, photons begin to have enough energy to move glass electrons from one energy band to another. For example, ultraviolet light, which has a wavelength ranging from 10 to 400 nanometers, can't pass through most oxide glasses, such as the glass in a window pane. This makes a window, including the window in our hypothetical house under construction, as opaque to ultraviolet light as wood is to visible light.


    If an electron is in the first energy level, it must have exactly -13.6 eV of energy. If it is in the second energy level, it must have -3.4 eV of energy.

    Let's say the electron wants to jump from the first energy level, n = 1, to the second energy level n = 2. The second energy level has higher energy than the first, so to move from n = 1 to n = 2, the electron needs to gain energy. It needs to gain (-3.4) - (-13.6) = 10.2 eV of energy to make it up to the second energy level.

    So here's the question, If an electron is in the first energy level, it must have exactly -13.6 eV of energy. If it is in the second energy level, it must have -3.4 eV of energy.
    Let's say the electron wants to jump from the first energy level, n = 1, to the second energy level n = 2. The second energy level has higher energy than the first, so to move from n = 1 to n = 2, the electron needs to gain energy. It needs to gain (-3.4) - (-13.6) = 10.2 eV of energy to make it up to the second energy level.
    If it takes 10 eV to move the electron in shell 2 , in the glass, and the iron block, then why does the glass electron not get excited when hit by a photon.
    Why is the iron electron absorbing.
    What makes a four inch cubed block of glass different to a four inch cubed block of opaque solid iron, what is the difference in the glass, and irons electrons, why is the glass block allowing transmission, and the iron block absorbing.
    Is it the amount of electrons in the shells in the iron, or is it the electrons in the glass need more eV compared to the irons electrons.
    What I am trying to do is find all the ways the electron in the atom can not be excited, by light, or any type of EM radiation, or another way to look at it is, how the electron can be kept in the ground state shell 1 the "1 shell" (also called "K shell"), and not get excited to shell 2.
    https://mail.google.com/mail/u/0/?ui=2&ik=1a702d60a0&view=fimg&th=15247bba1386a248&attid=0.2&disp=emb&realattid=ii_15247bad4c5acd4e&attbid=ANGjdJ_gB_S7X_IC6st087aolohQiGHeOtNC_3il-P0E4z3F-CUQOQR_q43rRRsTIDqe_YlK2AlLrjWiYTkFRSctQkU5Znv7P5E6sZNIDv5Yz6cBpDC4rbnb5uu7Avs&sz=w746-h320&ats=1452905705409&rm=15247bba1386a248&zw&atsh=1
    Thank you for your help.
     
  16. Jan 15, 2016 #15

    DaveC426913

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    Oh God please stop pressing the Post Reply button.
     
  17. Jan 16, 2016 #16

    mfb

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    Those numbers apply to atomic hydrogen only. They are different for everything else. Every material has different energy levels.

    Photons of visible light have an energy of about 1.5 to 3 eV.
     
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