A very large plastic sheet carries a uniform charge density of -6.00 nC/m^2 on one face. (a) As you move away from the sheet along a line perpendicular to it, does the potential increase or decrease? How do you know, without doing any calculations? Does your answer depend on where you choose the reference point for potential?

Video transcript

Hey everyone. So this problem is working with electric potential. Let's see what they're asking us. A huge class. Lambda has one of its faces charged uniformly at this negative charge, we need to state how the electric potential varies along a line perpendicular to the surface without making calculations. And it's asking if it's the result is the result dependent on a chosen potential reference point. Okay. So we know we can't um you know, do any calculations but we can make a drawing. So that's what I'm gonna do here and kind of talk through what the question is asking us. So we have a lamb in a right, it's this kind of infinitely large surface for all intents and purposes and it's negatively charged. Okay. And then we have a line that is perpendicular to the lamb Inna. And it's asking us how the potential changes, potential is usually given v. Changes as it moves along this line away from the laminar. So we need to start by considering the definition of electric potential. So let's recall that according to the definition, the potential along a path increases as a positive charge gains potential along it. Okay, so that means that the electric field produced by this lamb in a which is charged does not depend on the distance from the lamb inna and its uniform. So the field around this um lamin A is uniform and we know that the potential increases along the line perpendicular right? Because it's a positive, that's what we can expect from a positive charge. So from this we can conclude that work must be done on the positive charge to move it away from the negatively charged stamina. So when we go think about all of that and look at our answers, we know that it is be the potential increases along the line perpendicular to the laminate surface, and the result does not depend on the chosen potential reference point, because at any point on the lamin A, the electric field around the lamb in a is going to be the same. All right. That's all we have for this problem. We will see you in the next video.