Re: Basic Question

EskWIRED@[EMAIL PROTECTED]
 wrote:
> In sci.physics.electromag, jimp@[EMAIL PROTECTED]
 wrote:
>> EskWIRED@[EMAIL PROTECTED]
 wrote:
>>  
>> > Ummm....using any wire of any thickness and a given resistance per
unit of 
>> > length, why is it that more voltage will yield more current? Is it a 
>> > matter of velocity of electron flow?  
> 
>> Because E=IR which is basic Ohm's Law.
> 
> That I know.  The question is why.  

You mean why does Ohm's Law work?

The simple answer is you start with Maxwell and work your way into Ohm.

It was a homework problem and extended classroom discussion when I went to
school. Feel free to have the experience.

You can't get there without math.

>> The magnetic field propogates at c.
> 
> I thought that electromagnetic fields propogated at C only in free
space.  
> Doesn't a wire provide significant resistance?

Yes, but resistance has nothing to do with the velocity of propagation,
that is determined by the dielectric constant.

The velocity of propagation or velocity factor is a parameter that
characterizes the speed of an electomagnetic wave through a medium.

The VOP of free space is 1.

The VOP of a medium is the reciprocal of the square root of the dielectric
constant of the medium.

For a bare wire in air the VOP is about 0.99 as the dielectic constant
of air is about 1.0005.

For a wire covered with solid polyethylene the VOP is about 0.66 as
the dielectric constant of polyethylene is about 2.25.

> Are you saying that low voltage electricity travels at the same velocity

> as high voltage electicity?

Yes, the velocity of propagation depends only on the dielectric constant
of the propagation medium.

-- 
Jim Pennino

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