An Experiment About Parallel Circuit And The Lorentz Forces On Wires

TL;DR

This paper presents a simple experiment demonstrating how parallel circuits and Lorentz forces on wires can be observed and manipulated, providing educational insights and an alternative explanation for microwave thrust phenomena.

Contribution

The experiment illustrates the relationship between circuit topology, Lorentz forces, and magnetic effects, offering a new educational demonstration and an alternative explanation for microwave thrust observations.

Findings

Changing return path shapes alters Lorentz forces and torsion balance displacement.

The experiment can be easily reproduced in teaching labs.

Provides an alternative explanation for microwave thrust phenomena.

Abstract

Parallel circuit and the Lorentz forces on current carrying wires are important concepts in introductory physics courses. Here we describe an experiment that illustrates these two concepts. We mount a circuit with multiple grounding points onto a torsion balance. We show that the grounding points create parallel return paths for the supply current. When the topology or the shapes of the return paths are altered, the Lorentz forces exerted by the currents in the return paths within a magnetic field change accordingly, which in turn cause changes in the rotary displacement of the torsion balance. This experiment is simple and can be easily reproduced in a teaching laboratory. What makes it interesting to students is that recently two research teams have attempted to detect thrusts from microwave driven asymmetrical resonance cavities (EmDrive or Cannae Drive), and the phenomenon observable in this experiment provides an alternative explanation to the thrusts they detected.