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Homework Help: Simple conversion I thought?

  1. Feb 21, 2008 #1
    Near earth, the density of protons in the solar wind is 10.0cm^-3, and their speed is 691 km/s.
    To find the current density I need to multiply (nLA)e

    do i need to convert 10.0 protons cm^-3 to 10000000m^-3 because i tried that and it didnt work????
  2. jcsd
  3. Feb 21, 2008 #2


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    Science Advisor

    This is a simple case that you need to use consistent units to get a sensible answer.

    If you really want to use the units km/s for speed then you should use (km)^-3 for your density and expect an anwser in units Amps/(km)^2. Alternatively you could convert the speed to cm/s (leaving density in (cm)^-3) and that would get you an answer in units Amps/(cm)^2.
  4. Feb 24, 2008 #3
    i actually figured it out
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