 I mean, it's a compound problem, but you have to find the wavelength before you do anything anything else. And it tells you also to find the frequency. Okay, anyway, so let's read it, it says the hydrogen atom produces a very strong spectral line in the red region of the visible spectrum. This spectral line corresponds to the electronic transition from the n equals 3 energy level to the n equals 2 energy level. What are the wavelength and frequency of this light? So hopefully you can see Rydberg equation all over that, right? So what's the Rydberg equation, and in this case, lambda, yeah, that thing, lambda. So yeah, this is to start learning the symbol keys on your keyboard, actually, or your Greek letters if you want to think about it though. So 1 over n2 squared is 1 over n1 squared. Okay, n2, remember, is the final one, n1 is the initial one, so where does it go? It goes from 3 to 2, so n2 equals 2, n3 equals, oh, n3 equals n1 equals 3. So, is this, like what we were talking about earlier, I know this isn't talking about energy, but is this going to be negative in energy or positive in energy? Negative, right, because it's going from 3 to 2, that's like falling and splatting on the floor, right, it doesn't take any energy to fall off the desk, right, but it takes energy to climb up the desk, it takes energy to go from what, 2 to 3 or what, you know, but no energy, what do we solve it for again, point of length and frequency, right? So, I mean, plug and show, I guess you know the Rieberg constant and if you don't, it's given to you. How many positive, then? This is not, this is weight, not energy, I think this is always positive, right? It doesn't make sense that we make it a weight. That's what I mean, that's not, I was looking like Rieberg. Yeah, this is not that energy equation, right, Rieberg constant for the energy equation, remember, what is that? Yeah, that's what it does for the strong. It's going to be negative 2 to 18, right? So, that's where you get that negative from, 1 divided by 1.0, 9, 7, 8. I'm just going to write this whole thing down, 3, 6, 1, 4, right now. 100 meter, if you want to think about it like that. So, frequency, so we'll keep it in meters, okay? So, frequency, how do we do that? We just put it over, so you're cool with that now, right? Yeah, I was just wondering, like on the other one, I said you flipped it because of the nanometers, but I thought it was because of the... So, that's what we're getting right now, it's the weight. How do you set frequency? Oh, we're eventually going to get the frequency back. Maybe I miss both, but yeah. I mean, do we set anything? Nothing, so let's just do this to 4, just for fun. So, that's the weight point, right? Can we do that? Can we just divide that? Yeah, so, you just want it. Can I do that than that? Because again, this is having the meters on the bottom here, right? So, we have to get that meters on the top in order to do the flipping over. So, yeah, I didn't put that step. Okay, so now that we have the wavelength, frequency, and actually I don't need those anymore. So, c equals nu, there's another Greek letter for you, sometimes I'll call it c, but it's actually nu, lambda, and you know c, and if you don't, it's given to you. So, it's cool, I know mostly we want to put these in nanometers, but keep it in meters because you're going to have the meters here. So we're looking for frequency now, so frequency equals c divided by lambda, which equals 3.00 times 10 to the 8 meters per one second, and lambda is that, right? So, it's like 1 divided by 6.5, 6, 3 times 10 to the negative 7 meters, canceled, canceled. And frequency, of course, is in the value of hertz, right? The units of hertz, which is also the units of per second, which is what we got. So, again, like I always say, if you can cancel out your units, then you should be good. So, 4.57 to the 14, and that's per second, right? And hertz is the same thing as per second. Let's get that answered. Okay, any questions about this? If you didn't get that answer, then it's probably something, would you go with me? No, I don't. I'm just talking to you guys. Any questions, questions? Okay, dude, should I put it on the video? Okay, cool. Any other questions? No?