All modern electrical equipment is based on an understanding of the relationship between what two concepts?

The relationship between electricity and magnetism is foundational to modern electrical equipment. This connection is primarily described by electromagnetic theory, which explains how electric currents produce magnetic fields and how changing magnetic fields can induce electric currents. This principle is crucial in the functioning of various devices such as generators, transformers, and motors. For example, electric motors operate on the principles of magnetism created by electric currents, enabling the conversion of electrical energy into mechanical energy.

Understanding this relationship allows engineers and scientists to design more efficient devices and systems that utilize both electricity and magnetism. In this way, almost all modern electrical applications, from everyday household items to complex industrial machines, depend on the interplay of these two concepts.

While the other concepts mentioned—current and resistance, voltage and frequency, power and energy—are certainly relevant in specific contexts of electronics and electrical engineering, they do not encompass the broad foundational basis for electrical equipment as electricity and magnetism do. These latter concepts are typically derived from or used within the overarching framework established by the relationship between electricity and magnetism.