The unusual phenomenon of electromagnetic induction

Abstract

This paper describes the unusual phenomenon of electromagnetic induction that occurs when a Nd–Fe–B magnet is passed through a hollow paramagnetic aluminum tube and conduction of eddy current happens. It was observed that the time taken by the Nd–Fe–B magnet to pass through a 1 m aluminum tube is longer than that through a 2 m tube. A tentative theory for this phenomenon is that due to the paramagnetism of the aluminum tube, the 2 m tube induces a more potent induction to pull the Nd–Fe–B magnet downward than that present in the 1 m tube. This scientific effect, which is coined herein as a length-boost effect, can create a situation that contradicts the conventional thinking that it should take a longer time to fall through a longer tube. One application of this is in controlling the velocity of a falling Nd–Fe–B magnet by changing the length of the aluminum pipe. The other is using aluminum as braking fins in free-fall chairs at amusement parks to reduce heat dissipation. However, diamagnetic tubes, such as those composed of copper and brass, do not possess this effect. A magnet falling through longer tubes of these metals takes a longer time than through shorter tubes.