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Homework Help: Pls help me with my Resistivity Question in pHysics due tomorrow morning.

  1. Jan 20, 2009 #1
    Pls help me..thanks

    1. The problem statement, all variables and given/known data

    17. How long should a copper wire 20 mills in diameter be for it to have a resistance of 5.0Ω?

    20. An electric motor draw 10 A from a 240-V source 120 ft away. What is the minimum diameter of the copper wire in mills if the voltage drop is not to exceed 2%?

    22. A copper wire 1.0 mm in diameter carries a current of 12 A. Find the potential difference between two points in the wire that are 100m apart.

    24. The resistance of a copper wire is 100 Ω @ 20oC. Find its resistance at 0oC and at 80oC

    25. An iron wire has a resistance of 2.00 Ω at 0oC and a resistance of 2.46 Ω at 45oC. Find the temperature coefficient of resistivity of the wire
  2. jcsd
  3. Jan 20, 2009 #2


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    What is it you don't understand?

    You need to show some effort and identify where you are stuck.
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