Hey, everyone. Let's get started with this example problem here. So we're talking about the wave function of the electric field of this electromagnetic wave is it's this 54 sign of 2.2 times 10 of the seventh X minus omega T. So what we can see here is from our formula, remember this is the sort of general equation for an electric field. We can see that our 54 is actually our em ma and this two times 10 of the seventh is actually RK. But we don't know what the omega is. All right. So we have emacs and we also have K. So the first thing we need to do is we, we need to find the amplitude of the magnetic field. Remember whenever they're asking you for the amplitude, they're just asking you for the maximum value here. So they're asking for what is B max? All right. So how do we calculate B max here? Whenever you want to figure out either the strength of one of the fields, whether it's the electric field or the magnetic field, you can always relate it to the other one by using E equals CB now E equals CB works for anything. Uh But it could also be E max equals C times B max, right? So that works always. So in other words, the way we figure this out is by using E max equals C times B max. So we divide over the C and this really just becomes E max over C equals B max here. Now we're just gonna go ahead and plug in some variables. Now, remember this is just 54. So that's what we plug in for E max 54 divided by the speed of light three times 10 of the eighth. And what you should get is 1.8 times 10 of the minus seven. And that's in Tesla's all right. So that's your final answer for part A, let's move on to part B. Now, now we want to figure out what's the frequency of this electromagnetic wave number frequency is the variable F. So how do we do that? Well, you'll notice here the most easy, I guess the most direct way to figure out the uh frequency is by trying to relate it to the omega if you had omega. And unfortunately, in this equation, we don't have omega. Remember this is just a variable over here. It's something, it's some number that we just don't know. So instead we of using this omega equals two pi over F, we can't use this because we don't know what Omega is. But we do know what K is right. Remember K is just this variable over here or this number two times 10 of the seventh. So instead we can use this part of this equation here. Remember these three things are equal to each other. So whatever two of the variables that you have, you can always use those two to figure this out. So we want to figure out the frequency and we know what the K is. So now we just use this part over here two pi F equals C times K. Now we just divide the two pi over to the other side. So this is two pi and this becomes F equals uh CK over two pi. So I'm gonna start plugging in some numbers. So this is three times 10 to the eighth speed of light. Our K variable is two times 10 to the seventh number. It doesn't have any units. It's just a number and then we just divide by two high. Now, when you work this out, what you should get is you should get 9.55 times 10 to the 14th. And that is in Hertz. All right. So that is your final answer for the frequency of this electromagnetic wave. So you can always basically get um these variables K and omega from these two variables over here. All right. So let me know if you have any questions and I'll see you in the next video