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Homework Help: Need help plss

  1. May 17, 2004 #1
    Hi all,
    I've this question and I don't know how to go about... can somebody pls assist?
    a cylinder of glass 1cm long has a resistivity of 10E12 ohm meter. how long would a copper wire of the same cross sectional areqa need to be to have the same resistance as the glass cylinder?

    thanks in advance.
  2. jcsd
  3. May 17, 2004 #2

    Chi Meson

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    Homework Helper

    Resistance is directly proportional to both length and resistance. If cross-sectional area is constant, then to retain the same total resistance, the length of the copper wire will be the same fraction less as its resistivity is to that of glass. resistivityglass /resistivitycopper = lengthcopper / lengthglass
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