Boundary condition between conductor and free-space

1. May 1, 2014

yykcw

For an imperfect conductor, when there is current, an electric field is set up inside the wire along the direction of the current flow, and is parallel to the wire.
If this is true, then what I don't understand is
boundary condition tells me the tangential E-field is always continuous, if there is no E-field outside the wire, how come there will be E-field inside the wire?

2. May 1, 2014

maajdl

There must be some electric charge on the wire, and some electric field outside the wire.

3. May 1, 2014

yykcw

But isn't that those E-field outside is perpendicular to the wire?
I don't understand why tangential E-field will exist outside.

4. May 1, 2014

sophiecentaur

I think this is your problem. Imo, there will be an E field outside the wire which, for a straight wire, between two large flat plates (the easiest example I can think of), will bt ΔV/x where ∇V is the voltage drop (imperfect wire) and x is the length.

5. May 1, 2014