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Light and Heat Generation of Elements

  1. Sep 10, 2015 #1
    Hi forum,
    Is there anyway to quantify the proportions of light and heat energy generated from an element?
    I mean, is there a model which we can use to predict material energy conversion proportions when a voltage potential is applied to it.? Further, is the model able to predict material conversion capacities given only the atomic #, negativity or group?

    Thank you.
     
  2. jcsd
  3. Sep 10, 2015 #2

    mfb

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    What do you mean with "light and heat energy generated from an element"? If you just leave any element on a table, in general it does not produce light or heat. If some chemical or nuclear reactions happen then it might do that, the details depend on the element then. Sure, it is possible to calculate that.

    I don't see the relation to a voltage (where?).

    What do you mean with "material conversion capacities"?
     
  4. Sep 11, 2015 #3
    My apology for the lacking info, consider this simple presentation of what I meant (see figure) simple%20circuit.gif
    How much proportions of heat and light are being generated from the total dissipated energy of the load?
    Is there a model which predicts how much proportions of heat is being generated and proportions light with relation to an intrinsic property of a material?

    Law of Energy (Conservation of Energy) would help :

    EE = LE+HE ; where EE - Electrical Energy, LE-Light Energy, HE-Heat Energy

    Proportions are expressed simply as LE/EEx100%; HE/EEx100% vs. say conductivity or resistance of material (Classical and Stastical model perhaps)

    The goal is to predict how much lumen and heat proportions on any material, one would either make as a heater or a light filament.
     
    Last edited: Sep 11, 2015
  5. Sep 11, 2015 #4

    mfb

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    It mainly depends on the geometry of the wire in the light bulb and its resistance. The material does not matter much for typical light bulbs (as long as it does not melt, obviously). It does matter if you care about the lifetime, but that is a different question.
    The emission is roughly a black-body spectrum, and this spectrum depends on temperature only. Higher temperatures give a higher fraction of visible light relative to heat (infrared light).
     
  6. Sep 11, 2015 #5
    But different material lit different frequencies of spectrum at corresponding temperatures, right? Thus, there must be a material fit for its purpose, to give off light the most but less heat.
     
  7. Sep 11, 2015 #6

    mfb

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    See above: it is a good approximation of a blackbody spectrum which is independent of the material.
    Sure, there are small differences, but other considerations like the lifetime of the device are more important.
     
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