- #1

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Given E in a region of space ( [tex]\epsilon_{o} , \mu_{o}[/tex])

I should think of it as a free space or vacuum?

I should think of it as a free space or vacuum?

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- Thread starter robert25pl
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- #1

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I should think of it as a free space or vacuum?

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- #2

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This is vacuum.

- #3

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[tex] \nabla \times \vec E= -\frac{\partial \vec B}{\partial t} [/tex]

[tex] \nabla \cdot D=\rho [/tex]

In free space J = 0 so for J in vacuum I should use

[tex] \nabla \times H =J+ \frac{\partial D}{\partial t}[/tex]

or something else?

- #4

OlderDan

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robert25pl said:

[tex] \nabla \times \vec E= -\frac{\partial \vec B}{\partial t} [/tex]

[tex] \nabla \cdot D=\rho [/tex]

In free space J = 0 so for J in vacuum I should use

[tex] \nabla \times H =J+ \frac{\partial D}{\partial t}[/tex]

or something else?

You probably want to use

[tex]D = \epsilon_{o} E [/tex]

[tex]B = \mu_{o} H, [/tex]

to eliminate D and H. Don't know if you will need it, but you can round out your set of equations with

[tex] \nabla \cdot B=0 [/tex]

- #5

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[tex] \nabla \times H =J+ \frac{\partial D}{\partial t}[/tex]

I get J

What is the difference between free space (J = 0) and vacuum?

- #6

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So we can have sources in vacuum.But not in free space.

Free space is typically a vacuum in which electromagetic waves (radiation far away from the sources) propagate.

Daniel.

- #7

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Thanks, So in my problem I will get J not equal 0

- #8

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Please post the text of your problem in its exact form.

Daniel.

Daniel.

- #9

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[tex]E = (6z\vec{i}+10y\vec{j})cos500t \vec{j}[/tex]

Find [tex]B, \rho, J[/tex]

- #10

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[tex] \nabla\times\vec{E}=-\frac{\partial\vec{B}}{\partial t} [/tex] (2)

[tex] \nabla\times\vec{B}=\mu_{0}\vec{J}+\mu_{0}\epsilon_{0}\frac{\partial\vec{E}}{\partial t} [/tex] (3)

Daniel.

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