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Why does an alpha particle have 40mm range in air?

  1. Jul 2, 2015 #1
    Hey everyone...

    so I understand that an alpha particle, being a helium nucleus, is quite a large particle compared to, for example, a beta particle. Due to this, it will encounter a lot more collisions and impart its momentum to other particles of air at a much more rapid rate.

    Is there anything I'm missing here at a simple level? perhaps any equations that this is due to?
  2. jcsd
  3. Jul 2, 2015 #2


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    very simply ....

    the alpha particle will easily take a couple of stray electrons and become a stable Helium atom and thereby ceasing to exist as a radiating particle

  4. Jul 2, 2015 #3


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    First a wiki:

    From there to note that, the alpha particles are slow in comparison to beta and neutrons speeds. Also the charge is double. And only by these two you would get a lot more interaction with other charged particles on it's path.
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