Which term best describes the power source in a circuit?

The power source in a circuit is best described as a battery. A battery serves as the storage unit for electrical energy and provides the necessary voltage to push the current through the circuit. It converts stored chemical energy into electrical energy, allowing the circuit to perform work and supply power to various components such as lights, motors, and other loads.

In contrast, while a load refers to any component that consumes power within the circuit (like a light bulb or motor), a resistor is specifically a component that resists the flow of current, converting electrical energy into heat. A conductor, such as copper wire, facilitates the flow of electricity through the circuit but does not serve as the power source itself. Therefore, a battery is distinctly recognized as the primary source of electrical power within a circuit.