Falling magnets through coils in series: design and activities

Abstract

The aim of this article is to demonstrate an experimental apparatus that can be used to showcase ideas relating to electromagnetic induction (EMI). The apparatus is low-cost (‘home-made’) and consists of six N-turn coils wound and then joined electrically in series. The emf induced from a magnet falling through the center of the coils is then measured. From the data obtained, an accurate measurement of g can be found. However, the full data can also be analyzed to showcase some of the more subtle aspects of EMI that have been shown in the Physics Education literature to be sources of difficulty for students.