Final answer:
Joe is correct; an electric circuit refers to the complete, closed path through which electric current flows, composed of elements like batteries, wires, and loads in a closed loop.
Step-by-step explanation:
Between Joe and Tim's descriptions of an electric circuit, Joe's definition is correct. An electric circuit refers to the complete path through which an electric current flows. A circuit is composed of various elements like a power source, which can be a battery, conductors such as wires, and loads like lights or resistors. They all work together in a closed loop allowing electrons to move from the negative to the positive terminal, thereby creating a current flow. This can be visualized in schematics using symbols, where wires are shown as straight lines and resistors as zigzags.
Tim's description that an electric circuit refers to 'part of an electric current's path' is not accurate, as the term circuit implies a 'circle' or a return to the starting point, indicating a closed loop is necessary for an electrical device to function.