Electric Potential

by Patrick Ford
205 views
4
3
Was this helpful ?
4
Alright, guys. So in this video, we're gonna be talking about the electric potential. We talked about the electric potential energy between two charges. And even though those two things sound similar, we're going to see how in this video other different. Let's check it out. So electric potential is sometimes just simply called the potential and the electric potential energy is sometimes just simply called the potential energy. It's kind of assume that we're talking about electricity. So a lot of people just don't even say the electric potential energy. We just see the potential and the potential energy. But one important distinction to make is that even though these two things are related and they sound the same, they're actually represent different things. So we have to be very careful about our word choices between how we use these things. Now, the best way to understand what the difference is between a potential and a potential energy is to go back and talk about the way we explored what fields where electric fields. So he said that basically a single charge, whether it was a positive or negative charge, so I'm just gonna assume like it's a positive charge right here admitted these field lines, these electric field lines and basically these field lines were just information, and this information or field told charges that were in the vicinity. How much force to feel And basically what happens is that a single charge alongside with producing an electric field also produces something called an electric potential and sort of very similar as to how it works. So if you have a positive charge at the same time that it's producing this electric field outwards, that's telling other charges. How much force to feel? Well, a positive charge is also emitting some information a field called a potential, which, by the way, has the symbol V. And this symbol basically tells charges how much energy toe have or how much energy to feel. And the thing was, is that we were talking about single charges in which this was like a big queue. We said that that was the producing charge and then admitted this field lines and basically nothing happened unless you actually dropped a second charge inside of here. Q. And once you had a second charge. All of a sudden, now there is a force on this thing because if you have some electric field lines that point in this direction, and if you drop a charge here, then for instance, if it's a positive charge, then this is gonna feel a repulsive force like this. And we have the relationship between the force and the electric field that was just given as F equals q E. So once there is a second charge, there was a force well similar to potential right here. This single charge sets up a field called an electric potential, and once you drop a second charge inside of this potential, now there is energy. So these two things are different, but the mechanisms in which they sort of set up these force fields and energy fields is very similar now. We said that the force that we could calculate on a charge from an electric field is just given by this equation. F equals Q E. Well, it's very similar for energy. What happens is once there's a second charge that you put in between these two things. Now it basically creates some electric potential energy, which we know the equation for, and this electric potential energy is given as Q times V in which, in the case of cool OEMs law in the case of electric fields, this e represented the strength of the electric field that this feeling charge was put inside of. Well, this V is the strength of the energy field that is put inside off. So a lot. Another way you might might see that is actually the potential, sometimes the potential field. So basically, we know that the queue that this little Q here always corresponded to the queue that was feeling the field that it was put inside off. So, in other words, this Q is always the feeling charge. Well, it's the same way with the potential in this formula right here. U equals Q V. This cue always represents the thing that is feeling the potential at that specific spot. All right, so I just wanna go ahead and wrap up everything really quickly, once more, so you have a single charge. It produces something called an electric field, and that field tells charges that air inside of it, how much force to experience, and once that second charges put there, there's force called Columns Law, and it's given by this equation or cake over R squared, where is the strength of the electric field? And that Q. Is the feeling charged? Well with the potential. It basically does the same exact thing because if for energy and the equation slightly different, a single charge produces an electric potential out here. And once you in that potential tells charges inside of it how much energy toe have, And once there is a second charge, all of a sudden now there's energy. There's potential energy between these two charges that potential energy is given as U equals Q V or U equals K Q Q over our where that V is the strength of the energy field or the potential field. And this little Q is also the feeling charge. Okay, so the unit of this electric potential is called the Vault, and it's given by the letter V. And this V is actually defined as one Jewell per one. Cool. Um, now we have to be very careful here because this V is the symbol for both the electric potential. So it's actually like the symbol that we use, but it's also the same symbol for the unit. So, for example, it would be perfectly sensible. Toe have an equation like this. V equals three volts. This would be perfectly sensible. It was just some guy who decided hundreds of years ago that the symbol for the letter and the unit we're gonna be the same. So this right here is the symbol, which for electric potential. Whereas this right here is the unit. So just so you know, don't get confused between those two. And that's basically all we need to know about the electric potential. Let's go ahead and check out an example. We have a five and a three Coolum charge That air separated by some distance right here. So if the five Coolum charge feels 200 volts from the three column charge, what's the potential? Great. So we have these two charges right here. This is gonna be a five. Cool. Um, actually, let's do it the other way around. Let's do this. Is the three cool? Um, this is the five Coolum charge, and now we're supposed to figure out what is the potential energy on the five Coolum charge. So in other words, we're trying to figure out what you is. We know that you is just going to be K Q. One Q two over are Now, here's the problem here. We could use this. We could try to use this potential energy right here to figure out what the potential energy of the five. Oops. I didn't mean to do that. I didn't mean to write volts. I meant to write cool homes. We could use this formula to figure out what the potential energy of this five Coolum charges. The problem is, we actually don't know what this our distances so we can't use this potential energy formula. Instead, we're gonna have to use the different potential energy formula, which is that U is equal to Q times V. So we have with the charges. This charge corresponds to the feeling charge, and we know that we're the five column charge is feeling 200 volts from this charge over here. So, in other words, this is actually the producing charge Q. And this is actually the feeling charge little Q. So this is actually going to be the charge that we use in this formula and what we're doing is we're basically saying this producing charge here is producing some potential field, some some potential out in this field here. And this little cute is feeling it. Okay, So that means that this potential energy is just going to be the five cool OEMs times the potential, which is 200 volts at the specific point. So at right here, the Volta. Sorry that the votes, the potential is 200 volts. So that means that the potential energy is gonna be five times 200 which is equal to 1000, and that's it. So basically, just let me know if you guys have any questions, let's go ahead and do some examples.