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Designing an experiment to demonstrate Planck's Law

  1. Apr 10, 2015 #1
    For my undergraduate physics lab, we are asked to spend 3 weeks (3 3-hour sessions + any time during the week if I need extra time) doing an experiment of our own choosing. The physics department will provide any experimental tools needed within reason.

    I have been considering using this time to measure the intensity vs. wavelength of the light emitted from a tungsten filament at different temperatures. I would do this by focusing the emitted light through a lens then separating the wavelengths with a prism and finally detecting the intensity by wavelength with a spectrometer. I would then plot my data against the graph of Planck's law and determine how closely the two fit.

    Do you think that this would be a good experiment for this lab? Also do you think there are any other tools I would need? Maybe a voltage amplifier to get the Tungsten to a higher temperature? Can you think of any problems I would have?

    Thanks for your help!
     
  2. jcsd
  3. Apr 10, 2015 #2

    tech99

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  4. Apr 10, 2015 #3
    Is there a way that I could use a tungsten filament without the bulb/glass to avoid the infrared light being absorbed without the tungsten catching fire? Or is there another material that I could use to get a nice full Planck curve?
     
  5. Apr 11, 2015 #4

    tech99

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    I think a tungsten filament will work in air up to dull red, or evn organge with short.
    If you smash the glass envelope of a Tungsten bulb. I think the filament will operate in air for some time if you keep it to red or orange. You need to experiment. May I mention that I have found that glass lenses etc tend to warm up during an experiment, and then radiate IR.
     
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