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I Blue Light from a Blackbody Radiator

  1. Dec 15, 2017 #1
    From Wien's law it is seen that approx 6500K(Greater than sun's temp) needed to heat a body to blue! But we see so much blue light(uv ray)! Are they formed from any different mechanism rather than heating?
  2. jcsd
  3. Dec 15, 2017 #2


    Staff: Mentor

    Wein's law just describes the peak of the black body spectrum. A black body produces wavelengths both above and below the peak wavelength.
  4. Dec 15, 2017 #3
    My point is can we heat a blackbody to get mostly Blue radiation??
  5. Dec 15, 2017 #4


    User Avatar
    Gold Member

    Yes and no.

    From my research this morning, "Blue" is kind of a laymanishy term.

  6. Dec 18, 2017 #5


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    You'll pretty much never see a blackbody that appears violet though, since the eye's sensitivity drops so much below 450nm that even a blackbody that peaks in the UV will appear to be a brilliant blue. There's a chart on the wikipedia article about stellar classification (https://en.wikipedia.org/wiki/Stellar_classification), but basically any blackbody over about 10,000K will appear blue-white to blue. There are several stars visible to the naked eye that are fairly bluish (Rigel and Vega spring to mind), but you'll get a much stronger color impression if you look at them through binoculars or a telescope, since dim light doesn't tend to provide much color (the rods in your eye are much more sensitive than the cones, but they do not convey color information).
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