What’s the difference between Electric Potential and Electric Potential Energy? I’ve been trying to understand the difference but its not really working out for me :/
In: Physics
Charge.
Potential is a general, hypothetical thing. It tells you something about a point in space. It tells you how much potential energy something of unit charge would have if you put it there.
Potential Energy is the specific thing. It tells you about a particular object (or system). How much energy does this thing (or system) actually have.
If we have a point where the electric potential is *V*, and we put a particle with charge *q* there, the electric potential energy of that thing would be *U = qV*.
There is a similar relationship between an electric force and an electric field. The field tells you something about the point in space; how much would a thing of unit charge be forced if you put it there. The force tells you what happens to an actual thing; *F = qE*.
And you can get from force to potential energy, and from field strength to potential in the same way.
There is a whole bunch of maths behind this, and some more complicated physics, but that is the general idea.
Let’s use gravity to visualize the difference.
I have two balls at sea level, let’s call this 0 energy.
I then pick up the balls and raise them to a height, doing so requires an energy input that gets “stored” in the ball, aka “potential energy”.
Finally, let’s allow one ball is a tennis ball, and the other a cannon ball.
“Electric Potential” is analogous to Gravity and the height I raised the balls. Both balls would have the same “electric potential” in this case, because the make up of the balls themselves isn’t important, only gravity and height. At it’s simplest, it’s the difference between two points in a field – high and low. It’s based purely on the field itself and a dimension of space.
“Electric Potential Energy” now factors in the object itself, the weight of ball in my example, or the charge of the particle in the electrical example. Clearly a cannon ball will take more energy to lift and will have greater kinetic energy when it falls. So the nature of the ‘test object’ is important in this concept. In the electrical sense a very weak electric charge will react less (have less electrical potential energy) than a very strong charged particle, despite being the same field and the distance.
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