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Electromagnetic waves Conceptual help please

  1. Jan 31, 2009 #1
    Electromagnetic waves!!!Conceptual help please!!

    A long steel wire is cut in half is connected to a different terminal of a light bulb. An electromagnetic(EM) plane wave (E(x,y,z,t)=Esin(kx-wt)[y hat direction], B(x,y,z,t)=Bsin(kx-wt)[z hat direction]) moves past the wire.

    a) Suppose the wire were oriented parallel to the y-axis, with the bulb centered on the x-axis. Would the bulb glow?
    I said yes because the wire is parallel to the E field vector, causing the electrons in the wire to oscillate up and down crateing a current....Is my thinking corect or does the magnetic (B) vector affect it some how?

    B)Suppose nstead that the wire were positioned as described below. Would the brightness of the bulb be greater than, less than, or equal to the brightness that it had in part a. Explain your reasoning.

    i) The wire is parallel to the y-axis but its bottom end is located on the x-axis.
    I think that it will be equal to the brightness in case a because the E field is the same on a line, meaning they have the same magnitude no matter the distance from the graph.

    ii)the wire is tilted so that it makes an angle of 40 degrees with respect to the y-axis but is still parallel to the y-z plane.
    I am unsure about this one
    1. The problem statement, all variables and given/known data

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Jan 31, 2009 #2


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    Re: Electromagnetic waves!!!Conceptual help please!!

    In the wire current is induced only by changing magnetic field, not by changing electric field. And the current is maximum when the wire is perpendicular to the field.
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