ABSTRACT
Most people have some notion of the concept of energy, but few can formally define it . Before we try, we might consider an even more fundamental property of matter (e .g ., “mass”) . Because it is one of the four fundamental concepts of physics,1 mass is not rigorously defined . Informally, sometimes mass is defined as a measure of the extent of matter, or a measure of an object’s inertia . Given the existence of a physical object with mass, we can assign to it a property called “energy,” which is formally defined as the capacity to do work . Unfortunately, this definition does not immediately and fully clarify the nature of energy . There is of course no shortage of energy in the universe . Indeed, the universe is composed of only two entities: matter and energy!2 Broadly speaking, one can classify energy as being either potential or kinetic: that is, an object possesses energy by virtue of its position (“potential energy”) or of its motion (“kinetic energy”) . Energy can appear in various forms, including:
Mechanical Thermal, or heat Chemical Electrical Electromagnetic (radiant) Sound energy Nuclear energy
Humanity needs energy for lighting, heating, transportation, manufacturing, construction, and, sad to say, destruction . To direct energy to human needs, it is necessary to easily control it and convert it from one form to another, which prompts us to address a key question:
Why study energy in the electrical form?
