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Homework Help: Find the electrical field of a Spherical Shell

  1. Oct 12, 2009 #1
    1. The problem statement, all variables and given/known data

    Consider a thin spherical shell of radius 14.0 cm with a
    total charge of 32.0 %C distributed uniformly on its
    surface. Find the electric field (a) 10.0 cm and (b) 20.0 cm
    from the center of the charge distribution.

    2. Relevant equations


    3. The attempt at a solution


    I figured that the E(r) was the electrical field of the sphere.

    I did 9.9E9(32E-9/14^2) (also did it in meters too)

    I guess I am just completely lost in this one.

    Attached Files:

  2. jcsd
  3. Oct 12, 2009 #2


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    Homework Helper

    Electric field due to a charged sphere at a distance r is given by
    E = (1/4πεo)*Q/r^2
    In side the charged sphere, the electric field is .....?
  4. Oct 12, 2009 #3
    I got it.

    10cm < 14cm, so its inside, meaning = 0

    20cm > 14cm, so ke(q/r^2) = 8.99E9(32E-9/.2^2) = 7192, so now I just have to look over where I messed up on the order of magnitude

    7.192 MN/C from the center... is the answer!
  5. Oct 12, 2009 #4


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    Homework Helper

    In the problem, the charge is given as 32%C. What is that? micro or nano?
    If it is micro, the answer will be correct. You will get 7.192*10^6N/C or 7.192MN/C.
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