 So, this one sounds like a fun problem to do. An oil drop experiment gave the following charges on various oil droplets. Negative 6.4 times 10 to the 19th Coulomb's, negative 3.2 times 10 to the 19th Coulomb's, negative 8.0 times 10 to the 19th Coulomb's, negative 4.8 times 10 to the 19th Coulomb's. What value for electronic charge can you deduce from this data? Okay, so let's write down the stuff the problem gives us. So, it's saying that we have these oil drops, they have a certain charge on them. You recall from what we were talking about with the Milken oil drop experiment, what Milken actually had deduced was that the charge that he was seeing on each one of these oil droplets had to be, you know, multiple of the fundamental charge, okay? So that's what we're really looking for. Okay, so what is the common multiple of all of these things? So, the charge on the first one is negative 6.4 on the second one. Okay, so the way I would normally start to do a problem like this is to look at what the smallest number is. So, I guess, stepping back, we see that all of these are 10 to the negative 19th, so we can kind of not even, you know, think about that part of the answer or that part of the charge. So, in actuality, we can think of these as negative 6.4, negative 3.2, negative 8.0, and negative 4.8, is everybody okay thinking about those things? So, let's just write those down just to make ourselves recall that we think about them in this way now. Okay, so now I guess what I would do is look at the smallest number and see, can I multiply that by 2 and get the next smallest number, can I multiply? This number by 3 and get the next smallest number, can I multiply it by 4 or so on and so forth, okay? So, when I do that, what you'll find, right, is that you can't multiply 3.2 times anything to get 4.8, okay? And the difference between 8.0 and 6.4 is also not 3.2, so hopefully you guys have noticed that already. So, in fact, what you should be already deducing is that none of these is the fundamental charge, but it's actually something that's smaller than that, okay? So, I guess what we're talking about is this one has even more than one, what we would say, electron on that oil drop, okay? So, when we do this, what we can do is see, well, the difference between here and here, right, so 4.8 minus 3.2 is 1.6, so that's smaller than 3.2 and in fact, that's going to be the answer. You can already hopefully see it looking at those, but what you can say is, okay, can I divide each of these into 1.6 and get a whole number like an integer, okay? So, can I do that? So, let's do this, 6.4 divided by 1.6, so that's 4, so what is this saying? There's like 4 of these electrons on that particular oil drop. Is everybody okay with my thought process there? Okay, so here, right, of course, 3.2 divided by 1.6 is going to be 2, 8.0 divided by 1.6 and of course, 4.8 divided by 1.6 is going to be 3. So, hopefully you guys can see that there's whole number on each of these, right? So, none of these is the fundamental charge, but the fundamental charge is going to be that negative 1.6 times 10 to the negative 30. Do you think that's the greatest? Yeah, so the biggest multiple, yeah, that's what you want to think about. I mean, yeah, you can say it could be 0.8, right, yeah, a negative 0.8. Yeah, I guess in these types of problems, what they're looking for is the greatest multiple. Okay, this is a good question. Does everybody understand what he was talking about? So, if it was 0.8, all of these numbers would be double. It would be also a valid answer to this question. Probably the best would be, hopefully, like a multiple choice question in this sort of instance, you know, and I don't know, they don't give you two of those types of multiple answers, you know? What was 1.6, the required value of the value? So, it's going to be the fundamental charge in this particular case. Per atom, right? Per atom. Per electron. Per electron. Yeah, per electron. Does that answer your question? Yeah. So, it's like how much, so when we're talking about like an electron, right, a minus charge so normally we say that's minus one, you know, but in actuality it's not minus one like Coulomb's or something like that, it's actually, you know, in this case, negative 1.6 times 10 to the negative 19.