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Resistance and wire length

  1. Sep 26, 2015 #1
  2. jcsd
  3. Sep 27, 2015 #2


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    Do not accept any sentence you read on the Net.

    That first post you refer to assumes that the volume of the wire is kept constant. So you stretch out a piece of wire and see how its resistance changes.
  4. Sep 27, 2015 #3
    Volume of wire is the area of the cross section of the wire times its length - excluding any wire that has varying thickness, for now. Volume remains the same if the wire is somehow going to get "thinner" when it's being stretched.
  5. Sep 27, 2015 #4
    well if we assume that the density of the wire doesnt change then volume= mass/density... as mass of the wire is constant the volume has to be constant
  6. Sep 28, 2015 #5


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    The op at that link wasn't clear what he meant by the length of wire being doubled so the person that answered assumed he meant stretched. In which case the volume would be constant.

    I believe the op actually meant doubled as in two lengths joined together. In which case the resistance would double.
  7. Sep 28, 2015 #6


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    totally agree with that summary ... unclear question leading to a incorrect answer
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