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Re: R = V/I ?



Ahhhh philosophy, would a logical positivist say the definition is in the method?

So much fun to argue about philosophy.

my rather old dict. writes:   Resistance  3 Elec. "The opposition offered by a substance or body to the passage through it of an electric current."

that dict. defines ohm using the equation. (one volt per amp.)

the legal or international ohm was the resistance offered ... by a column of mercury ...

(the ampere was defined by the rate of deposit of silver from silver nitrate in an electrochemical cell, now probably using a current balance.  E is still (up to '49) by the law.)

bc
 

Mark Sylvester wrote:

At 12.29 05/05/00 -0500, Richard W. Tarara wrote:
>Another reason to avoid this usage is the confusion it causes the beginning
>student.  They may look at R = V/I and say OK, if we increase V then R
>increases.  While this might happen (to some extent) with a light bulb, it
>is definitely not the behavior we use Ohm's Law to describe.  Again, we have
>the problem of just how students interpret equations.  Many will look at
>them as definitions rather than functional relationships.  In my mind, the
>only time to use R = V/I is in a situation where you know both the voltage
>across and current through an object and want to know the resistance.  In
>this sense, the relationship gives you a MEASUREMENT of R but not a
>definition of R.

Hmmm... what, then, is the quantitative definition of R?

Mark

_____________________________________
Mark Sylvester
United World College of the Adriatic,
34013 Duino TS, Italy.
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