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Homework Help: Electron beam of a computer monitor

  1. Feb 1, 2009 #1
    1. The problem statement, all variables and given/known data
    The current in the electron beam of a computer monitor is 410 µA. How many electrons per second hit the screen?


    2. Relevant equations



    3. The attempt at a solution
    A beam current of 410µA means that 410µC of charge strike the screen per second. This is equivalent to (410e-6C)/(1.6×10-19C/e) = 6.56e-23 electrons...

    But it's telling me that it's the wrong answer, any help is appreciated!
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Feb 1, 2009 #2

    mgb_phys

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    Science Advisor
    Homework Helper

    I don't think you mean 10-23electrons
    410 x10-6 / 1.6 x10-19 = 410/1.6 x10-6 - -19 = 250 x10-6 +19 = 250 x10+13

    It's worth knowing the rules for doing calculations with exponents so you can estimate the answer before entering the numbers in a calculator
     
    Last edited: Feb 1, 2009
  4. Feb 1, 2009 #3
    Oops, calculator error, thanks!
     
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