Let us conceptualize an imaginary construct to help us understand the potential difference across a uniform electric field. This useful conceptual game may also help prepare us for electric circuits much later. Let us imagine a gravitational analog to a DC circuit.

Imagine wooden stairs and a croquet ball. It takes a certain amount of work to carry the ball up the stairs (joules per kilogram). Likewise, in a DC circuit, a battery does work in moving charges from low potential to high potential (joules per coulomb).

Releasing the ball down the stairs leads to the evolution of sound energy from the system as it bounces down. This release of energy is analogous to the heat evolved in a DC circuit from a resister which often derives from the collision of charged particles in the current with the atoms of the resistor medium.

Now imagine that instead of a uniform gravitational field, you have a uniform electric field, and instead of croquet balls, you were moving electric charges from a low potential energy position to a high potential energy position. This is analogous to the work performed by a redox reaction in a galvanic cell, for example. Now, instead of the energy stored in the system through the work being later released as a ball rolling loudly down some stairs, imagine instead the charged particles coming back down the potential gradient within the tungsten filament of an incandescent lightbulb.

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