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cksoon11
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Homework Statement
For a harmonic uniform plane wave propagating in a simple medium, both [tex]\vec{E}[/tex] and [tex]\vec{H}[/tex] vary in accordance with the factor exp(-i [tex]\vec{k}[/tex].[tex]\vec{R}[/tex])
Show that the four Maxwell’s equations
for a uniform plane wave in a source-free region reduce to the following:
[tex]\vec{k}[/tex] [tex]\times[/tex][tex]\vec{E}[/tex]= [tex]\omega\mu[/tex][tex]\vec{H}[/tex]
[tex]\vec{k}[/tex] [tex]\times[/tex][tex]\vec{H}[/tex] = [tex]\omega\epsilon[/tex][tex]\vec{E}[/tex]
[tex]\vec{k}[/tex] [tex]\bullet[/tex] [tex]\vec{E}[/tex] = 0
[tex]\vec{k}[/tex] [tex]\bullet[/tex] [tex]\vec{H}[/tex] = 0
Apparently "Vector k and Vector R are the the general forms of wave number and position vector(or direction of propagation)"
Question Source(no.4) :http://www.lib.yuntech.edu.tw/exam_new/96/de.pdf"
Homework Equations
You supposed to use Maxwell's Equations for a plane wave
[tex]\nabla[/tex] x [tex]\vec{E}[/tex] = -i[tex]\omega\mu[/tex][tex]\vec{H}[/tex][tex]\nabla[/tex] x [tex]\vec{H}[/tex] = i[tex]\omega\mu[/tex][tex]\vec{E}[/tex]
[tex]\nabla . [/tex] [tex]\vec{E}[/tex] = 0
[tex]\nabla . [/tex][tex]\vec{H}[/tex] = 0
The Attempt at a Solution
First off,I am confused as to how k can be a vector when it is the wave number(a scalar).
From what I can tell,the wave is propagating in the radial direction in spherical coordinates.
I then assumed the electric and magnetic fields to be orthogonal in the [tex]\theta[/tex]and [tex]\phi[/tex] direction.
But just simply substituting the phasor form of the plane wave into Maxwell's equations:
E[tex]_{o}[/tex] exp((-i [tex]\vec{k}[/tex].[tex]\vec{R}[/tex]) into Maxwell equations doesn't seem to yield the desired results because I don't understand how they obtained the cross-products and dot products of [tex]\vec{k}[/tex]with [tex]\vec{E}[/tex] and
[tex]\vec{H}[/tex].
I just can't seem to grasp the concept of a vector as my wave number.Could someone please phrase the question in more concise terms?What am I misunderstanding here?
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