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Mohammad_93
Oct22-10, 05:19 AM
Hi,

Does electric field in vacuum have the speed of light in vacuum?

If so, does it also in copper have the same speed of light in copper?

I and my friend have been arguing, and are waiting your response.
THANKS in ADVANCE
DaleSpam
Oct22-10, 07:09 AM
Does electric field in vacuum have the speed of light in vacuum?What do you mean by this? Are you trying to analyze solutions of Maxwell's equations where there is no magnetic field? If so, then you can only get static solutions which have no speed at all. If you are talking about wave solutions then the E field and the B field both propagate at the speed of light.

If so, does it also in copper have the same speed of light in copper?No, the speed of light in copper is less than the speed of light in vacuum.
Mohammad_93
Oct22-10, 11:13 AM
No, the speed of light in copper is less than the speed of light in vacuum.

No no, it's not a comparison between the speed of light in vacuum and in copper, but I'm comparing the speed of electric field in copper to the speed of light in the same material.

What do you mean by this? Are you trying to analyze solutions of Maxwell's equations where there is no magnetic field? If so, then you can only get static solutions which have no speed at all. If you are talking about wave solutions then the E field and the B field both propagate at the speed of light.

I don't even know Maxwell's equations,

All I want to do is know how much time the effect of charges (electric field) needs to move from the beginning of a wire to the end of it.

& thanks for reply
DaleSpam
Oct22-10, 11:49 AM
All I want to do is know how much time the effect of charges (electric field) needs to move from the beginning of a wire to the end of it.That is the speed of light in copper.
Mohammad_93
Oct22-10, 11:58 AM
Thank you very much,

In order for my friend to be convinced and completely sure, do you have some documented source stating explicitly that this speed is the speed of light in copper?? It will be really helpful
Thank you very much,
DaleSpam
Oct22-10, 03:23 PM
I don't have any real documentation. It is a direct result of Maxwell's equations.