Again on Motional EM Induction: Reply to H. Montgomery
| Scientific Paper | |
|---|---|
| Title | Again on Motional EM Induction: Reply to H. Montgomery |
| Read in full | Link to paper |
| Author(s) | Jorge A Guala-Valverde |
| Keywords | action a distance, fields, B-field |
| Published | 2007 |
| Journal | Apeiron |
| Volume | 14 |
| Number | 1 |
| No. of pages | 3 |
| Pages | 47-49 |
Read the full paper here
Abstract
The paper by H. Montgomery published in this issue, exhibits a curious mix between local action models (fields) and non local (action a distance) prospects. When dealing with the motor configuration (Section 4, figure 7), Montgomery makes use of the (Amperian) surface currents instead of the B-field itself. By analysing the case B (the probe anchored to the turntable in the singularity), he recognizes, according to Newton's third law, force cancellation between the probe and the rims of the singularity: the probe becomes unable to spin the magnet. Astonishingly, he adds: but the more distant parts of the magnet still produce a force on the probe These few words deserve caution since for a field theoretician the suitable tool for force calculations is Laplace's expression, dF = I dl x B, where B is the magnetic field in which the wire is immersed, but not the distant field. Conversely, the field model works when applied to the closing circuit wire, which (being in true contact with the B-field ) is the responsible for the observed counter-clockwise rotation. When dealing with the generator configuration (Section 3, figure 5), a similar sketch is offered by Montgomery. The first time derivative of the B-field can be detected in the laboratory, but not at points fixed on the turntable. In other words, on the probe (according to Montgomery, the seat of the induced emf) there will be ? B/ ? t = 0, as if the turntable were at rest in the laboratory.
