Sorry - an obvious mistake!
Near the end of the post below, for F=q(VxB) please read F = q(E + VxB)
Bob Sciamanda
----- Original Message -----
From: "Bob Sciamanda" <trebor@VELOCITY.NET>
To: <PHYS-L@lists.nau.edu>
Sent: Saturday, May 04, 2002 4:12 PM
Subject: Re: induced emf again
| | Why are the "two distinct phenomena" not recognized
| | in our introductary textbooks? Why don't we have two
| | distinct names for two distinct phenomena? Would it
| | be better to say that "motional emf" is different from
| | "induced emf?" How come that both emfs can be
| | calculated by the same formula? Only a coincidance?
| | Ludwik Kowalski
|
| In the final analysis, both phenomena are reducible to charged particle
| interactions, expressible as the effects of the fields of the "source"
| charges on "recipient" charges. I tend to think of these things in this
| way:
| 1) a stationary charged particle produces an electrostatic E field
| following Coulomb's inverse square distance law;
| 2) a charge moving at a constant velocity also generates a magnetic B
| field described by the Biot-Savart law ;
| 3) an accelerating charge also generates a non-conservative E field
| described by Curl(E) = -dB/dt or E = -dA/dt, where A is the vector
| potential (whose Curl is B);
| 4) the interactions of charges can be described as the effects of the
| above fields on "recipient" charges through the relation:
| F=q(VxB).
|
| Our calculational language sometimes obscures this basic
| particle-interaction physics.
|
| Bob Sciamanda (W3NLV)
| Physics, Edinboro Univ of PA (em)
| trebor@velocity.net
| http://www.velocity.net/~trebor
|