What is 'K' in K=1/4pi Epsilon 0?

  1. Hey So for those that don't know, I'm reading this from Atomic Physics, basically where they teach you how the size of a nucleus was determined by shooting alpha particles at it. due to repulsion an alpha particle can get only 'so-close' to nucleus(they're both positively charged), and the the so-close is labelled as point P, the closest to the nucleus and alpha gets.

    So heres a formula they teach us to use:

    1/2mv2 = kQq/r

    What is k called? what is the name of this constant, and what is it equal to since I was told it was the electric constant and went about solving it with that value, but at the back in the answer section they used the value 9x10^9!!
    Thanks guy!!! :D
     
  2. jcsd
  3. tiny-tim

    tiny-tim 26,055
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