Re: [Phys-l] induced emf and induced current

[Bernard Cleyet <bernardcleyet@redshift.com>]

I thought EMF originally applied to electro-chemical cells.

bc  will henceforth use literage meterage, celciusage (kelvinage),  
hertzage, etc. along with voltage and amperage.


Wiki. "thinks"  its definition is

Voltage is commonly used as a short name for electrical potential  
difference.


and:


"In conduction processes occurring in metals and most other solids,  
electric currents consist almost exclusively of the flow of electrons  
in the direction B to A. This movement of electrons is controlled by  
differences in a so-called "total local thermodynamic potential"  
often denoted by the symbol µ ("mu"). This parameter is often called  
the "local Fermi level" or sometimes the "(local) electrochemical  
potential of an electron" or the "total (local) chemical potential of  
an electron". The modern electron-based definition of voltage (VA −  
VB) is in terms of differences in µ:"


Note the caveats:

http://en.wikipedia.org/wiki/Voltage

Finally:

"A common misapprehension is to assume that difference in voltage is  
always equal to difference in electric potential (i.e. electrostatic  
potential). This is often untrue, because differences in "chemical  
effects" (e.g., as between conductors made from different materials)  
also contribute to differences in µ, and hence to differences in  
voltage. Some textbooks (especially old physics textbooks) give  
historic definitions of voltage that are not strictly equivalent to  
the modern definition. However, the difference in value between a  
"voltage difference" and the related "electric potential difference"  
is always small (at most a few volts, often less), and in many  
contexts it is commonplace (and acceptable) to disregard the  
distinction. Nonetheless, in some contexts, such as the theory of  
contact potential differences, the distinction is vital."




On 2009, Oct 10, , at 09:56, John Denker wrote:

> Depending on context, "emf" translates to:
>  -- the plain old voltage
>  -- the Thévenin equivalent open-circuit voltage
> __________________