How does a closed circuit produce light in a bulb?

A closed circuit allows electric current to flow continuously within a complete path, enabling the electrical energy produced by a battery to travel through wires to the bulb. In this process, the electrical energy encounters the filament or the light-emitting component inside the bulb. This energy causes the filament to heat up to a point where it produces visible light through incandescence or excites gas atoms in a way that emits light.

The flow of energy is crucial; without a complete circuit (meaning the path is closed), the current cannot move, and the bulb will not light up. Therefore, the direct movement of energy from the battery, through the connections and wiring, to the light source is what facilitates the production of light. This understanding reflects the fundamental principles of circuits in physics and electrical engineering.