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Re: B and electric charge



25 would be OK but I want to have the same
units as SI. That is how my freedom of choice
was used.

----- Original Message -----
From: Jack Uretsky <jlu@HEP.ANL.GOV>
Date: Sunday, January 6, 2002 2:24 pm
Subject: Re: B and electric charge

I took seriously your labeling of the constant as "arbitrary",
Professor Kowalski, so why can't I use 25?
Your faithful student,
Jack

On Sat, 5 Jan 2002, Ludwik Kowalski wrote:

My arbitrary constant was ~9,000,000,000,
not 25. As far as the current is concerned
I will post a puzzle in another message.
It deserves its own thread; I will call it
a paradox. But first let me see if this
message, composed in the public library,
finds its way to Phys-L.
Ludwik Kowalski

----- Original Message -----
From: Jack Uretsky <jlu@HEP.ANL.GOV>
Date: Saturday, January 5, 2002 11:03 am
Subject: Re: B and electric charge

Here's one waiting for your return:
How about going in baby steps, though, like you're the
teacher and
I am trying to understand what you are doing (not much of a
stretch).> > We've agreed on definition of charge, as
described previously.
The arbitrary constant is 25 N-m^{2}/C^{2}; an equal charge pair
givinga force of 1 N at a separation of 1 m is 1/5 C. Now I hear
you talking
about currents. How do I measure a current (I understand that
it is
"flowing charge" and 1 A = 1 C/s)?
How do you answer your student?
Regards,
Jack


On Fri, 4 Jan 2002, Ludwik Kowalski wrote:

Ludwik Kowalski wrote:

What I would like to discuss is the definition of B.
Why do we define it in terms of the EFFECT of the
magnetic field and not in terms of what CAUSES it?
Instead of introducing B via the Lorentz law (directly
or indirectly) we can introduce it via the Bio Savart
law. Which way is pedagogically more desirable and
why? I have no opinion so far.

Actually the question should have been asked differently.
Why do we first show what the field does and then how
it is produced? In other words, why Lorentz first and
Biot-Savatr later? Would the reversal be desirable or not?
The formal introduction of B should match the conceptual
sequence chosen, as it does in most textbooks.
Ludwik Kowalski


--
"But as much as I love and respect you, I will beat you and I will
killyou, because that is what I must do. Tonight it is only you
and me, fish.
It is your strength against my intelligence. It is a veritable
potpourriof metaphor, every nuance of which is fraught with
meaning."> > Greg Nagan from "The Old Man and
the Sea" in
<The 5-MINUTE ILIAD and Other Classics>



--
"But as much as I love and respect you, I will beat you and I will
killyou, because that is what I must do. Tonight it is only you
and me, fish.
It is your strength against my intelligence. It is a veritable
potpourriof metaphor, every nuance of which is fraught with meaning."
Greg Nagan from "The Old Man and the Sea" in
<The 5-MINUTE ILIAD and Other Classics>