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Homework Help: Please, can someone help me quickly with these two problems

  1. Apr 9, 2008 #1
    Please, can someone help me quickly with these two problems!!!!!

    1. The problem statement, all variables and given/known data
    A parallel plate capacitor is constructed with a dielectric constant ( k = 3 * 10^8) The maximum projected voltage is 5000v and the capacitance needed is .5 micro Farads. Calculate the plate area.

    2. Relevant equations
    Q =VC, C = AE/d, C = KC


    3. The attempt at a solution
    Well, I can solve for Q, but that doesn't help. Also I don't know d!. Is 5 microfarads before or after the influence of the dielectric?

    Another one, please :)
    1. The problem statement, all variables and given/known data
    Compute the capacitance on a cylindrical capacitor of length 5cm. This capacitor consists of two hollow concentric cylinders with radii of 1.5mm and 4mm (surface area of cylinder is 2pirl)

    2. Relevant equations
    2pirl, Q=VC


    3. The attempt at a solution
    I don't know the cylinder equations!
     
  2. jcsd
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