In all three cases (the rod, the rotary generator and the battery) the
internal resistance is physically distributed between the device
terminals. For calculational (mathematical modeling) purposes we
represent the composite device with the Thevenin equivalent of an emf in
series with an internal resistance.
Consider that if your rod were short circuited by a super-conductor, the
current would be limited by the rod's resistance.
Bob Sciamanda (W3NLV)
Physics, Edinboro Univ of PA (em)
trebor@velocity.net http://www.velocity.net/~trebor
----- Original Message -----
From: "Bob Sciamanda" <trebor@VELOCITY.NET>
To: <PHYS-L@lists.nau.edu>
Sent: Saturday, May 04, 2002 9:07 AM
Subject: Re: induced emf again
| | I think that the one ohm resistance of the rod does
| | not contribute to the current because motional emf
| | (voltage causing the current) exists between its end
| | points. Otherwise rod's resistance would act as it
| | were an internal resistance of a battery and i1 would
| | be 250 mA. Note that the effect of the magnetic field
| | produced by a current is ignored; it would not be
| | significant in this case.
| | Ludwik Kowalski
|
| The rod resistance acts the same as the armature resistance in a
generator
| (in fact, that is what it is). In both cases it must be included as the
| internal resistance of an emf device - as you would do with a battery.
|
| Bob Sciamanda (W3NLV)
| Physics, Edinboro Univ of PA (em)
| trebor@velocity.net
| http://www.velocity.net/~trebor
|