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Homework Help: Dielectric help

  1. Feb 6, 2008 #1
    [SOLVED]Dielectric help

    1. The problem statement, all variables and given/known data

    To make a parallel plate capacitor, you have available two flat plates of aluminum (area = 180 cm2), a sheet of paper (thickness = 0.10 mm, k= 3.5), a sheet of glass (thickness = 2.0 mm, . k= 7.0), and a slab of paraffin (thickness = 10.0 mm, k= 2.0).
    (a) What is the largest capacitance possible using one of these dielectrics?
    (b) What is the smallest?
    2. Relevant equations

    [tex]C=k\epsilon_0 \frac{A}{d}[/tex]

    3. The attempt at a solution

    I used the above equation to evaluate the capacitance of each in this manner:
    1) 3.5*8.85e-12*.180m^2/.0001 = 5.5755e-8
    2) 7.0*8.85e-12*.180m^2/.002 = 5.5755e-9
    3) 2.0*8.85e-12*.180m^2/.010 = 3.186e-10

    I recorded the largest as .55.755 and the smallest as 318.6 (in their appropriate units) both of which were wrong. Any ideas where I messed up?
    Last edited: Feb 6, 2008
  2. jcsd
  3. Feb 6, 2008 #2
    self-solved it. 180cm2 is .018m2, not .180m2 as I have recorded.
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