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Homework Help: Help on Circuit HW problem

  1. Nov 20, 2006 #1
    A parallel-plate capacitor with only air between the plates is charged by connecting it to a battery. The capacitor is then disconnected from the battery, without any of the charge leaving the plates.

    Part A:
    A voltmeter reads 46.0 V when placed across the capacitor. When a dielectric is inserted between the plates, completely filling the space, the voltmeter reads 15.0 V. What is the dielectric constant of this material?

    Part B:
    What will the voltmeter read if the dielectric is now pulled partway out so it fills only one-third of the space between the plates?

    I know how to do part A using K = Vo/V, But i do not know how to work the problem if it involve partial dielectric.Any helps or hints would be great thanks.
  2. jcsd
  3. Nov 20, 2006 #2


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    Science Advisor
    Homework Helper

    Think of the system as two separate capacitors. Are they arranged is series or in parallel?
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