Re: capacitance of a disk

[brian whatcott <inet@INTELLISYS.NET>]

Interesting. That seems to confine the uncertainty of
a given capacitance value to the physical dimensions of its size
and the relative permeability of its dielectric then....

Perhaps about one part per million, would you say?

Brian

At 13:45 2/11/01 -0600, Jack Uretsky wrote:
>        The value of epsilon_0 is a defined quantity (like the speed of
> light, to which it is related) so that it is known with infinite
> precision.  It's value is 1/[mu_0*c^2] where mu_0=4pi*10^(-7)N/A^2.
> All of this courtesy of my PDG Booklet.
>                                        Regards,
>                                                Jack
> On Sun, 11 Feb 2001, brian whatcott wrote:

> > An innocent reader (like me) might easily speculate on how exact
> >  a result can be which depends for its magnitude upon
> >  a physical quantity like epsilon_0  - the permittivity of free
> > space, six decimal places known with certainty from my data
> >  book reference.
> >
> >  The permittivity of air could contribute a difference
> > in that sixth decimal place?
> > (Relative permittivity of air = 1.000536)


> > At 17:04 2/10/01 -0500, David Bowman wrote:
> > > // the exact general result for the
> > > capacitance (to infinity) of an arbitrary conducting oblate spheroid of
> > > semimajor axis a and eccentricity e (the formula being simple enough to
> > > readably write in ASCII), it is
> > >
> > > C = 4*[pi]*[epsilon]_0*a*e/arcsin(e)   .
> > >
> > > David Bowman
> > > David_Bowman@georgetowncollege.edu


brian whatcott <inet@intellisys.net>  Altus OK
                Eureka!