Re: Ohm's Law

[Bob Sciamanda <trebor@VELOCITY.NET>]

That simply hides the definition in "rho" - must rho be independent of V?
Besides this definition is not wide enough - it is a calculational tool
and refers to rather limited geometries and contains no reference to the
"current response" of the material to Voltages, the essence of the cincept
resistance (that is all hidden in the unspoken definition of rho).

Would you define volume as L x W x H? . . . (4/3)Pi r^3 ?  They are
calculations for certain geometries, but don't define the essence of the
concept "volume".

Bob Sciamanda (W3NLV)
Physics, Edinboro Univ of PA (em)
trebor@velocity.net
http://www.velocity.net/~trebor
----- Original Message -----
From: "Rick Tarara" <rtarara@SAINTMARYS.EDU>
To: <PHYS-L@lists.nau.edu>
Sent: Friday, February 08, 2002 12:16 PM
Subject: Re: Ohm's Law


> ----- Original Message -----
> From: "Bob Sciamanda" <trebor@VELOCITY.NET>
>
> > Good point - I don't like it, but we do that with other definitions
(eg.,
> > it is kosher to regard one or more of Newtons "laws" as definitions).
> >
> > More importantly, if R= V/I is a statement that the resistance is
> > independent of voltage, where is the definition of resistance (R)?
>
> How about  R = rho(T)L/A?
>
> where rho is the temperature dependent resistivity of a material.
>
> Rick
>
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