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Homework Help: Can somebody pls explain the concept?

  1. Apr 25, 2004 #1
    Hi All,

    A wire of length 1 m has a resistance of 0.3 ohm. it is uniformly stretched to length of 2 m. what is the new resistanct?

    I'm not sure how to express the concept / equation?

    pls guide me...
  2. jcsd
  3. Apr 25, 2004 #2
    I'm not sure, but I'd guess that the resistance is inversely proportional to the length of the wire.
  4. Apr 26, 2004 #3
    Resistance is directly proportional to the length of the wire, and inversely proportional to the cross sectional area.
    As the length increases, so does the resistance.
    As the cross sectional area decreases (wire getting thinner) the resistance will increase.
    R=p(L/A) Where p is the resistivity of the wire. This is a characterstic of the material itself to either conduct or insulate. It is not changed in your question.
    However, by this equation you can see the effect of the length (L) and the Area (A) on the resistance of the wire.
    I hope this helps you.
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