Question about Coulomb

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3 total messages Started by Doug Dias Mon, 02 May 1994 15:19

#1590

Author: Doug Dias
Date: Mon, 02 May 1994 15:19

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 Here's another question posed by students:
Historically, where did the amount of charge on an electron get its value
from? I know that a Coulomb is based upon an Ampere, but before they were
defined, where did the actual value originate?  This is more of a history
question, than physics, but we were wondering...

Re: Question about Coulomb

#1524

Author: Thomas Karch
Date: Fri, 06 May 1994 06:03

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Doug Dias (dougdias@COPERNICUS.BBN.COM) wrote:
:  Here's another question posed by students:
: Historically, where did the amount of charge on an electron get its value
: from? I know that a Coulomb is based upon an Ampere, but before they were
: defined, where did the actual value originate?  This is more of a history
: question, than physics, but we were wondering...

Historically I would say the milestones for the discovery of the elementary
charge are
- Millikans oil drop experiment (e/m) and
- J.J. Tompsons actual 'discovery' of the electron.

Everything with refinements of course, to find the 'real' value...
(Of course the real value will never be known, unless you redefine your 
units as in the case of the velocity of light)  

Thomas

Re: Question about Coulomb

#1461

Author: Joe Bellina
Date: Thu, 12 May 1994 23:06

29 lines
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Millikan using his oil drop experiment found a smallest value of charge on
a drop of oil which he claimed to be a single charge, ie of the electron. 
There was no mass involved.  With the charge to mass determined by J.J>
Thomson, the mass of the electron was known.


In article <2qcmj3$8v5@news.tamu.edu>, t0k6704@tamsun.tamu.edu (Thomas
Karch) wrote:

> Doug Dias (dougdias@COPERNICUS.BBN.COM) wrote:
> :  Here's another question posed by students:
> : Historically, where did the amount of charge on an electron get its value
> : from? I know that a Coulomb is based upon an Ampere, but before they were
> : defined, where did the actual value originate?  This is more of a history
> : question, than physics, but we were wondering...
> 
> Historically I would say the milestones for the discovery of the elementary
> charge are
> - Millikans oil drop experiment (e/m) and
> - J.J. Tompsons actual 'discovery' of the electron.
> 
> Everything with refinements of course, to find the 'real' value...
> (Of course the real value will never be known, unless you redefine your 
> units as in the case of the velocity of light)  
> 
> Thomas

-- 
Joseph Bellina (jbellina@saintmarys.edu)

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