What is a circuit?

A circuit is defined as a closed loop that allows electric current to flow. This means that for electricity to travel and perform work, it needs a complete path. When the circuit is closed, the electrical current can move through the conductive materials, allowing devices such as light bulbs or motors to function. Each component within the circuit, including the power source, wires, and any load (like a light bulb), is connected such that electricity can flow continuously.

In contrast, the other options describe concepts that do not accurately depict what a circuit is. Storing energy pertains to batteries or capacitors, which do not define a circuit but rather components within some circuits. A device that transforms energy refers to tools like generators or motors that change one form of energy to another, which is also not synonymous with a circuit itself. An open system of electrical connections does not function as a circuit because an open circuit lacks a complete path for current to flow, meaning that no electrical current can travel through it. Therefore, stating that a circuit is a closed loop best captures the fundamental characteristic of how electricity operates in electrical systems.