 So let's take a look at this emotional EMF practice problem that I gave my students. And again, this problem is on blackboard if you want to print out the full worksheet. So in this problem, you have an airplane with a wingspan of 60 meters, which is flying horizontally towards the east with a speed of 250 meters per second. If the plane is flying through a region where the magnetic field is directed vertically away from the ground with a field strength of 5 e to the minus 6 Tesla, what is the induced EMF between the wing tips? So this is a basic emotional EMF equation. And in this case, your magnetic field, the length, which is your wingspan, and your speed are all perpendicular to each other. And we're solving for the EMF. Now just going back to the problem again, I've highlighted a few things here. So that length is your wingspan and that's 60 meters. Your velocity is your speed of 250 meters per second. And the field strength that you need to use is 5.0 e to the minus 6 Tesla. And what you're solving for is the induced EMF. Now on the second part of the problem, after you've plugged in all those numbers, we're looking for which wing tip will have a higher potential. And I gave you the hint of drawing the diagram. So I'm going to go just a little further here and actually show you a diagram just to make sure that everybody's clear. So you're going to start by looking down on the plane towards the ground. And so we have our normal northeast, southwest. The plane is flying towards the east so you could draw a little figure like this. And here's your velocity. And again, the wingspan is your length and that goes from north to south. In this problem, the B field goes away from the ground. And since we're looking down towards the ground, that means the B field is out of the screen. So we can show that as our series of dots. Once we've kind of gotten that geometry shown out, and again this highlights the fact that I have a velocity, a length, and my magnetic field which are all at right angles perpendicular to each other. For my right hand rule, your thumb is going to go along the velocity so it's going to point towards the right. Your magnetic field is your fingertips and that's going to point out of the screen towards you. You've got to kind of twist your hand a little bit so that your right hand is pointing out of the screen towards you with your thumb off towards the right. When you look at your hand in that direction, you'll see that your palm is facing down towards the bottom of the screen. And so that means you're going to have some positive charges build up over here because that palm is the force on positive charges. Similarly, your negative charges are pushed in the opposite direction so they would accumulate up here at the top of the wingspan. So then the question remains, once we've done that, is what's at a higher potential? The area where it builds up positive charges or the area where it builds up negative charges? So I haven't fully solved this practice problem for you. You're going to have to go in and do the math on part one and then answer this question but make sure that you've drawn out your diagram so that I can see that you went through these steps. So that's the end of this example. Make sure that you actually go through and do all of those worksheets so you can turn it into me in class on Tuesday.