Torsion Balance Experiment About Unipolar

Unipolar induction which once was a inexplicable phenomenon in physics is a special case of electromagnetic induction. Beginning from Faraday, scientists and engineers in the nineteenth and twentieth centuries attempted to understand unipolar induction by using magnetic lines of force, there were striking controversies. It was only in the twentieth century, with the general acceptance of Maxwell's equations and the principles of relativity, that a consensus on unipolar induction could emerge.In this paper, we review the history of unipolar, and also give a description of a series of experiments. With Maxwell's equations and the principles of relativity, a model of a uniformly magnetized iron bar is discussed. Using the experience of our laboratory, we design an experiment of a torsion balance. The detail of the experiment is depicted in this paper. The result of our experiment is figured out by numerical computation. Disturbance like the electromagnetic field and the acceleration of the electromotor which is the driver of magnet or the pressure of remnant air in the vacuum is discussed. We give the primary result of our experiment. And improvement of the experiment is also brought forward.