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Finding an electric field on a disk using surface charge density

  1. Jan 29, 2012 #1
    1. The problem statement, all variables and given/known data

    A disk of radius 2.30 cm has a surface charge density of 5.22 μC/m2 on its upper face. What is the magnitude of the electric field produced by the disk at a point on its central axis at distance z = 11.2 cm from the disk?

    2. Relevant equations

    Formula for an electric field

    3. The attempt at a solution

    (int)dEz= sigma/2ep0 (1-z/sqrt(z^2+r^2)
  2. jcsd
  3. Jan 29, 2012 #2
    Break up the disk into elementary rings and integrate.
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