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Electric Field Distribution of a disk

  1. Sep 23, 2012 #1
    Hi can someone help me with this problem?

    A thin disc of radius 60 cm has a hole its center of radius 30 cm. A total charge of
    10^-3C is distributed uniformly on its surface. Find E at a point P which is 10 cm. on the central axis of this disc.
    What would be the acceleration of an electron passing through point P ?. Mass of electron = 9.11*10^-31 Kg.

    How would I set up dq for this?
    would it simply be dq= σ2∏rdr? and if it is what is the numerical value for σ?

    Thank you!!
  2. jcsd
  3. Sep 23, 2012 #2


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    2017 Award

    Staff: Mentor

    You have a uniform charge distribution. Can you calculate the total surface area of your disk? This should give you σ.

    If you use the symmetry of the setup, you can use that.
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