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Physical meaning of parts of electromagnetic wave

by littlepapa87
Tags: electromagnetic wave
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Sep24-10, 02:13 PM
P: 4

E = E_0exp i(k dot r - wt) or E = cos(k dot r - wt)

what does k dot r physically represent? Can r be any position in space or must it lie on the wave?

(I physically understand what a dot product is)
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Dr Lots-o'watts
Sep24-10, 03:06 PM
P: 674
That's a plane wave, it occupies all of space.

If you want a beam that is localized along a line, E_0 has to be a function of distance from the line.
Sep24-10, 05:19 PM
jtbell's Avatar
P: 11,735
Quote Quote by littlepapa87 View Post
Can r be any position in space

or must it lie on the wave?
A 3-dimensional plane wave fills space. It doesn't lie "along" a line or other single path. See the diagram and associated instructions in the following post for a more realistic picture of a plane electromagnetic wave than you see in many textbooks.

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