This Hall effect phenomenon was pointed out in an AJP article to show that
there is a non-zero, radially varying charge density in the current
carrying wire interior. I believe the author was Peters (?). I remember
citing the article in previous discussions on this list concerning charge
distributions in/on current carrying wires. If you like, I think I can
resurrect the reference.
Bob Sciamanda (W3NLV)
Physics, Edinboro Univ of PA (em)
trebor@velocity.net http://www.velocity.net/~trebor
----- Original Message -----
From: "Eric T. Lane" <elane@CECASUN.UTC.EDU>
To: <PHYS-L@lists.nau.edu>
Sent: Monday, November 18, 2002 6:26 PM
Subject: Question 07/02 CURRENT IN A WIRE
| In freshman physics we are told that a current in an "infinite"
| cylindrical wire flows with constant density J independent of this
| distance from the center of the wire. But we also learn how to use
| Ampere's Law to calculate the magnetic field in the wire. Doesn't the
| magnetic field act to make the current density non-uniform?
|
| Answer: 11/02 The Hall Effect explains this question. A charge moving in
| a magnetic field experiences a force perpendicular to its velocity and
| to the magnetic field. Charges moving in a wire will shift to one side
| of the wire producing a charge separation. This charge separation gives
| rise to an electric field. The charge continues to shift until the
| force of the electric field exactly balances the magnetic force. Then
| the current continues straight on, since the two forces exactly cancel.
| Inside a wire carrying a uniformly distributed current, the Hall Effect
| generates a small radial electric field that exactly cancels the
| influence of the magnetic field produced by the current thus
| maintaining the uniform distribution of current in the wire.
| . . .
This posting is the position of the writer, not that of SUNY-BSC, NAU or the AAPT.