Unofre B Pili, Wilfred V Rios, Rommel G Bacabac
This article details a supplementary investigation on the electric fields due to a uniformly-charged ring and a line of charge. Specifically, this study examines the well-known textbooks’ approximations associated with these classic problems in elementary electromagnetism: rings and rods behaving as point charges. The analytical approach presented in texts is rather cursory, which is based on the supposition of large distances and as a consequence, hiding potentially relevant effects, pertaining to location, regime, or transition. The intended ease in this approximation could lead students to the unintended consequence of its liberal use. This scenario unnecessarily exposes students to further misconceptions. This study is aimed to help students overcome potential pitfalls by providing a more intuitive presentation of the problem. To achieve this, a simple remedial visualization approach, based on synthetic data, is used, demonstrating the transition from the electric fields of the ring and rod to that of a point charge. © 2026 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved. This article is available under the terms of the IOP-Standard License.
Department of Physics, University of San Carlos, The Philippines, Cebu City, 6000, Philippines; Medical Biophysics Group—Center for Tissue Engineering and Biological Soft Materials, University of San Carlos, The Philippines, Cebu City, 6000, Philippines
