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Definition of unit of electric current

  1. Jun 30, 2010 #1
    The ampere is that constant current which , if maintained in two straight parallel
    conductors of infinite length, of negligible
    circular cross-section
    , and placed 1 metre apart in vacuum, would produce between
    these conductors a force equal to 2 × 10 ^{–7} newton per metre of length.

    What is meant by orange colored text??
  2. jcsd
  3. Jun 30, 2010 #2


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    Yes - and your question is ?
  4. Jun 30, 2010 #3


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    It means that one considers the limit that the wires are infinitely thin.
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