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Drift velocity of electrons

  1. Oct 27, 2011 #1
    1. The problem statement, all variables and given/known data
    A potential diffference of V = .497 V is applied across a block of silicon with resistivity 8.75 x 10-4 Ωm. The dimensions of the block are width = a = 2.00 mm, and length L = 14.7 cm. The resistance of the block is 54.1Ω, and the density of charge carries is 1.23x1023 m-3. Assume that the current density in the block is uniform and that current flows in silicon according to Ohms Law. The total length of 0.507mm diameter copper wire in the circuit is 79.1 cm. Assume that the resistivity of copper is 1.72x10-8Ωm for this problem.

    On average, how long does it take an electron to pass from one end of the block to the other?

    2. Relevant equations
    Δt = L/Vd = Lanbe/i

    3. The attempt at a solution

    L = .145 m
    a = .002 m
    n = ?
    b = ρsL/aRs = .00121 m
    e = ?
    i = 9.55 mA

    Can someone please help me with the values for n and e? Thanks
  2. jcsd
  3. Oct 27, 2011 #2
    Your n value would merely be the density of charge carriers per unit volume.
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