Potential difference and power

When a torch bulb is connected to a bettery, electrons deliver energy from the battery to the torch bulb. Each electron takes a fixed amount of energy from the battery as it passes through it. The electrons then deliver energy to the bulb as they pass through it. After delivering energy to the bulb, each electron re-enters the battery via the positive terminal to be resupplied with more energy to deliver the bulb.

Each electron in the battery has the potential to deliver energy even if the battery is not part of a complete circuit. The battery supplies each electron with electrical potential energy. When the battery is in a circuit, each electron passing through the circuit component does work to pass through the component and therefore uses some or all of its electrical potential energy. The work done…