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Homework Help: Surface Charge/Electric Field

  1. Jul 9, 2008 #1
    Space vehicles traveling through Earth's radiation belts can intercept a significant number of electrons. The resulting charge buildup can damage electronic components and disrupt operations. Suppose a spherical metallic satellite 0.9 m in diameter accumulates 2.2 µC of charge in one orbital revolution.
    (a) Find the resulting surface charge density.
    C/m2
    (b) Calculate the magnitude of the electric field just outside the surface of the satellite, due to the surface charge.
    N/C

    2. Relevant equations
    a. Looking at the units I need the answer in, I assumed that the surface charge density is charge/area or C/m^2.
    for this problem that would be Q /(pie x r^2) or 2.2e^-6C / (pie x .45^2)

    So I solved and got 2.2e-6/.6361725124 = 3.458e-6

    This is not the right answer - I can't find part a which should be easy - a little help please.
     
  2. jcsd
  3. Jul 9, 2008 #2

    G01

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    Gold Member

    The satellite is spherical in shape.

    The area you have is the area of a circle, not the surface area of a sphere...
     
  4. Jul 9, 2008 #3
    wow - thanks - I knew there was something obvious I was over looking
     
  5. Jul 9, 2008 #4

    G01

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    No problem. Glad I could help.:smile:
     
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