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Homework Help: Find Electron Current Through Iron Wire

  1. Apr 29, 2016 #1
    1. The problem statement, all variables and given/known data
    What electron current is driven through a 1.4-mm-diameter iron wire by a 0.070 V/m electric field? The mean time between collisions in iron is 5.2×10^−15s .
    A=1.5*10^-6 m^2
    ne=8.5*10^28 m^-3

    2. Relevant equations
    I know I need to use ie = neAVd, but I'm having trouble finding the drift speed.

    3. The attempt at a solution
    I set up ie = neAVd , as I currently know both ne and A, but the vd value is what's throwing me off. I multiplied the collision speed by the electric field strenght and got vd=3.64*10^-16m/s, which led to a final answer of ie=4.6*10^7 electrons/s. However, I was wrong and the answer is 8.4*10^18 electrons/s.
  2. jcsd
  3. Apr 29, 2016 #2


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