24. Electric Force & Field; Gauss' Law
Electric Field
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Hey, guys. So in this video, I want to talk about electric fields. It's something that you'll see in your textbooks. You'll need to know how to solve problems with it. But it's also to answer a very important question, which is how to charges exert forces on one another. And the basic answer is that they do them by setting up these things called electric fields. So basically a single charge right which I'll call big Q is gonna produce an electric fields. You might see some confusing definitions in textbooks, but basically the idea is it's kind of like information this big. Q is setting up this thing called an electric fields right that exists in all directions. And then, if you place another charge at some distance, little are away from this produced electric field, then this charge will feel that field and actually have a force on it. So, in other words, it will have a repulsive or attractive force here, which we know from cool arms law. So basically what happens is this thing. Regardless of whether there's another test charge or another secondary charge to feel it, this thing produces an electric field in all directions. And then when you place a charge inside of that field, it feels of force. And that force that it's felt with the electric field is which is set up by big Q is just Q times E in which he has units of Newtons per Coolum, right? You probably don't need to know that, but there it is anyways, So he has units of Newtons per cool. Um, Okay, now which Q are we gonna use in these questions? Well, that Q is always the one that's feeling the force. So the words the secondary charge right here. Now, some of you might be wondering, Whoa, isn't the opposite also happening? Doesn't this Q also produced its own electric field and therefore this one is felt by it, and the answer is yes. So this little Q also produces an electric field that is either felt an attractive or repulsive force. And this is basically how to charges exert forces on one another. You have action reaction because of these things called electric fields. Okay, so again, I just want to reiterate in problems the queue that you're gonna use inside of this f equals qu equation is always gonna be the one that feels the charge or the the electric force. At some distance, little are okay. It's a simple is that Let's go ahead and take a look at an example. We've gotta to cool um, and three Coolum charge. They're separated by some distance. Are So I'm gonna go ahead and set these up. I've got to Cool. OEMs. Uh, got to cool. OEMs. Three columns. They're separated by a distance of little are in such a way that the electric field at this point is 10 Newtons per Coolum. In other words, we have an electric field here at this distance. Oh, sorry, Actually have it backwards. So this is actually gonna be the three Coolum charge, and this is gonna be the too cool in charge. Now, the electric field at this distance is just 10 Newtons per Coolum. And now we have to feel what we have to figure out. What is the force on this to Cool? Um, charge. What does that mean? That means that this is the Q, and this is the big Q. So it all depends on which one is the feeling charge and which one is the producing charge. So this one the too cool in charge is the feeling charge. So in order to figure out the force, we just need Q times E So the force is gonna be Q, which is too cool homes times the electric field at this particular point, which we're told is 10 Newtons per Coolum. And that's just equal to 20 Newtons. Okay, so that's just a simple example. Let's go ahead and get into some or examples involving electric field.
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