RE: The Poynting vector, wire length and inductance (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

---------- Forwarded message ----------
Date: Fri, 28 Sep 2007 10:08:19 -0400
From: "Lau, Gary" <Gary.Lau@xxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: RE: The Poynting vector, wire length and inductance (fwd)

It has been known for longer than any of us have been around that the
inductance of a solenoid is proportional to the number of turns,
squared.  As the wire length is proportional to the number of turns, it
follows that the inductance is also proportional to the wire length,
squared.  Is this the extent of the point that you were trying to make?
I see nothing new here and don't see the need to drag calculus and
Poynting vectors into this.

Gary Lau
MA, USA

> Sent: Friday, September 28, 2007 8:42 AM
> To: tesla@xxxxxxxxxx
> Subject: The Poynting vector, wire length and inductance (fwd)
> 
> The source was an electromagnetics  text book. We took the E field
equations
> for a solenoid  and multiplied the numerators and denominators by  a
factor
> of 2pi and regrouped.
> 
> There are no solenoids with indeterminate wire lengths. Thus we are
entirely
> justified with this step as it reflects physicality.
> 
> When we include this information we can see that the E field is along
the
> entire length of wire (no big surprise is it?)
> 
> We can also see that the voltage is impressed across the entire length
of
> wire (no big surprise is it?)
> 
> Hence wire length is a squared function in the classic inductance
formula.
> 
> Jared Dwarshuis
>