Is there any relationship between the energy stored in an electomagnetic field

[Neil9327]

Is there a link here?

 

So on the one hand, the energy stored in the electromagnetic field created by a (constant DC) current passing through a coil (from its inductance L), and the kinetic energy of the electrons themselves passing around the link.

 

And a follow-on question (assuming no such link) is whether there is any effective contribution to the inductance of a wire from the kinetic energy of the electrons in the (constant DC) current flowing through it.

What are the equations?

[TonyMcC]

Neil - With regard to the last point the inductance is a physical property of the wire or more usually coil. It is rather like resistance is a physical property of a piece of material. Taking a coil wound around some magnetic material to cover the factors involved we can say that inductance depends on number of turns of wire, diameter of coil, the coil length and the type of material it is wound on. If you have a straight piece of wire it has no inductance at all. For more details you could go to http://www.allaboutcircuits.com/vol_1/chpt_15/3.html

[granpa]

no a straight piece of wire definitely has inductance. its just very small

 

the effect of inductance corresponds to the effect of mass.

so the mass of the electrons would in theory add a very very tiny amount to the inductance.

 

likewise, a tiny part of the mass of the electron is due to the electrons magnetic field

 

http://en.wikipedia.org/wiki/Biot%E2%80%93Savart_law#Point_charge_at_constant_velocity

Edited November 27, 2010 by granpa

[TonyMcC]

OK granpa, looks like you might have got me. The formula usually used to calculate inductance is :-

L=N^2(uA)/1 . For a straight piece of wire N is given the value of 1 (not zero). As you say the amount is tiny. For example if you are considering a circuit in that amount of detail you would have to include resistance of connecting wires and capacitance between leads forming parts of the circuit etc.. If dealing with more than 1 inductor you would have to calculate mutual inductance however far apart the inductors were. A very simple way of looking at it is the impossibility of making a complete circuit out of a straight wire. Your circuit would have one loop! In fact I'm not too sure whether we should say the inductance we are talking about is that of a single loop that the straight wire forms part of. Anyway looks like you are right - you nit picker you! lol (From another grandad).

Edited November 28, 2010 by TonyMcC

[swansont]

It may be better to sum up inductance as a property of geometry as opposed to (or perhaps in addition to) that of the wire. As to the OP, the energy of the electrons is given by V, which will be related to the energy stored in the field.