Does a straight non-time-dependent E field create a circular B field?


by zheng89120
Tags: circular, field, nontimedependent, straight
zheng89120
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Sep20-11, 10:54 AM
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I was under the impression that it does, you know from Ampere's law. But today, my professor told me that Electric and Magnetic fields are very similar (although I can't imagine they are exactly the same, since there are no magnetic monopoles), THAT a non-time dependent E field does not create a circular B field. Does this mean that a current in a wire is actually a time-dependent E field?

Thanks.

PS. the course that this was from was Relativistic Electrodynamics.
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Bill_K
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Sep20-11, 11:26 AM
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No, in this example there is no E field. It's the current in the wire that creates the B field.
vanhees71
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Sep21-11, 03:05 AM
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Nevertheless, relativity tells us that there is not a seperated E and B field, but only one electromagnetic field. If you have in one frame of reference a pure electrostatic E field in another frame of reference, moving relative to the first, you have both an E and a B field. Both fields together make up the electromagnetic field. (E,B) are the components of an antisymmetric 2nd-rank tensor in Minkowski space.

Bill_K
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Sep21-11, 04:10 PM
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Does a straight non-time-dependent E field create a circular B field?


That's quite true, but has nothing to do with the present thread. The question was, "is the current in a wire actually a time-dependent E field?" and the answer is no.
TrickyDicky
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Sep22-11, 07:08 AM
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Quote Quote by Bill_K View Post
No, in this example there is no E field. It's the current in the wire that creates the B field.
Actually, there was at some moment an E field (for the current to be there in the first place) but no longer there is, whether one decides to attribute the B field to this E field change or to the actual current it makes no difference at all.


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