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How did they measure the charge of electron

  1. Mar 12, 2012 #1
    I know that a charge is discribed in terms of coulombs. But how did they know that an electron has a charge of 1.60217646 × 10-19 coulomb ? by the way , what is a coulomb exactly ? and how did they found or discribed its quantity ? I would like the answer to be in details please . Thanks
     
  2. jcsd
  3. Mar 12, 2012 #2
    Look up the Millikan oil drop experiment.

    A coulomb is exactly that amount of charge which results from a current of one Ampere flowing for one second.
     
  4. Mar 12, 2012 #3
    you said it is " the amount of charge which results from a current of one Ampere flowing for one second " ,, what is Ampere ? and how would we find it ? ( suppose we want to calculate the charge and the magnitude of the charge is not given)
     
  5. Mar 12, 2012 #4

    tiny-tim

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    Welcome to PF!

    Hi Boody! Welcome to PF! :smile:
    The ampere (small "a" :wink:) is defined in terms of ordinary mechanical units.

    From the PF Library

    the amp is that current which in a pair of wires a metre apart would produce a force between them of 2 10-7 N/m​
     
  6. Mar 12, 2012 #5
    Re: Welcome to PF!

    mmmm, I see

    Thanks :)
     
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