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calculate wavelength from a known distance and color for Helium

  1. Apr 28, 2008 #1
    Hi all!

    I just joined the forums and hopefully my question is in the right place and isn't a lame one but I'm stuck so here goes:

    I want to know how to calculate wavelength from a known distance and color for Helium. I need exact wavelength. I already have the ranges obviously. Usually it's wavelength=c/v but I don't have frequency so any help would be greatly appreciated. Thanks.

  2. jcsd
  3. Apr 28, 2008 #2
    What do you mean by distance?
    Also color is frequency... so presumably if you know one - you know the other.
  4. Apr 28, 2008 #3
    sorry, I just realized that I was given a chart of Helium Wavelengths and the distances are to be used for something else:


    I have six colors: violet, Blue, Green, Orange, Yellow, and Red which all have ranges.
    violet: 380-420
    blue: 440-470
    green: 500-520
    orange: 580-620
    yellow: 550-580
    red: 620-700

    I think I am supposed to pick the wavelength from the given chart based on these ranges. Most work except for yellow. Yellow is in 550-580 and I don't see a wavelength that would fit in this range that is given above. And I must have six colors so I can't ignore the yellow.
  5. Apr 28, 2008 #4
    what about the 587.6, its pretty close?
  6. Apr 29, 2008 #5
    Yeah I guess, I will have to use that. I don't see another option. Thanks anyway, i guess this doesn't really count as a legitimate question; more of a weird data setup issue.

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