You measure the electric field of an electromagnetic wave at a particular moment and find it points in the +z direction. The magnetic field points in the +y direction. In which direction is this wave traveling?

Hey, folks. Welcome back. Let's just get some more practice here. So in this problem, we have the electric field of an electromagnetic wave, is pointing in the plus z direction. The magnetic field points in the plus y direction, and we wanna figure out basically what direction the wave is traveling. So we're trying to figure out the direction of an electromagnetic wave. We're always just gonna use our right hand rule. So let's just go ahead and draw sort of a three-dimensional coordinate system. This is actually just one of a few different ways to draw it. But basically, this is just gonna be the plus x, this will be the plus y, and this will be the plus z direction. Now it doesn't tell us what the shape of the wave is. All it does is tell us that the that the direction of the electromagnetic field is pointing in the plus z direction. So what does that mean? Remember that a wave can sort of go up and down like this, in which the electric field oscillates between up and down, or it could basically go forwards and backwards like this, which the electric field will sort of, like, point forwards and backwards or something like that. And it could also oscillate in the y axis. All this is just telling us here is that the direction at this particular moment points along the plus z axis. So at this little point here of this wave, the electric field points in this direction. This is gonna be e. Now the magnetic field points in the plus y direction, so it's gonna point up here like this. This is gonna be b. So then how do we find the direction the wave is traveling? We use the right hand rule. And remember, the rule is you point your fingers along the direction of the electric field, and then you curl them towards the magnetic field. So you curl your fingers this way. So curl. And then basically, your thumb is gonna point in the direction of the wave the the the wave's direction. Right? The wave's speed. Alright. So what happens here, is this is kind of weird because you're gonna have to sort of contort your hand a little bit. But basically, your your hand is kind of gonna look like this. My fingers are pointing out towards you and then when you curl them towards the magnetic field, your thumb should point in the to the left like this. Alright? So your thumb points off into the negative x axis. So this is basically where the wave's direction is. It's off to the left, and again, this is just gonna be where your thumb is. So in other words, the answer is the negative x, axis. Alright. Or negative x direction rather. And that's the answer. Alright, folks. Let me know if you need any, any help, and I'll see you in the next video.

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You measure the electric field of an electromagnetic wave at a particular moment and find it points in the +z direction. The magnetic field points in the +y direction. In which direction is this wave traveling?

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