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Homework Help: Force between two long straight wires

  1. Oct 8, 2011 #1
    Two long straight thin conducting wires run in parallel. The distance between them
    is d and the length of each wire is l. One of the wires is charged with charge +Q, the
    other wire with charge -Q

    (a) Calculate the strength of the electric field E(Q; d; l) generated by one wire at the
    location of the other wire.
    (b) Calculate the total force F(Q; d; l) exerted by one wire on the other wire.
    (c) What is F for a length of 1 m, a distance of 1 mm and a charge of 1 C?

    for (a) I finished with... kQ/ld^2
    for (b) I finished with... kQ^2/ld^2 using F=qE
    for (c) I got an answer of 9000N which seems way too big.

    I think I must have gone wrong somewhere
  2. jcsd
  3. Oct 8, 2011 #2


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    Staff Emeritus
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    It doesn't really help to simply post the incorrect answers you got and then ask what went wrong. We can't tell without seeing your work. Show us what you did.

    BTW, the units don't work out for (a), so your answer can't possibly be correct.
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