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Homework Help: Spherical Uniform Charge

  1. Apr 17, 2009 #1
    1. The problem statement, all variables and given/known data

    The figure below shows a spherical shell with uniform volume charge density ρ = 1.63 nC/m3, inner radius a = 6.0 cm, and outer radius b = 2.70a. What is the magnitude of the electric field at the following radial distances:
    r=1.5, r=b, r=3b

    2. Relevant equations

    Q= sigma dV
    flux = E x A
    flux = charge enclosed/permittivity constant (8.85e-12)
    k x q/r^2 = E (electric field outside a spherical shell of charge)

    E = k x r(q/R^3) R= radius r= distance from center of shell to point where E is measured.

    3. The attempt at a solution
    I've tried integrating, and substituting different values of q into the Electric Field equations. I've gotten 18094, 82, and 1813 as answers. I would show my integration techniques, but it's kinda hard to do on the keyboard. haha
  2. jcsd
  3. Apr 17, 2009 #2
    Part I:
    When r = 1.5, what's charge inside the sphere of r = 1.5 m?

    When r = b or r =3b, that sphere encloses all the charge. So, Q is same but Area changes for part II and part III
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