Millikan Oil Drop Experiment

Everyone. So here we're going to say that in 1897 JJ Thompson's Cathode ray to experiments led to discovery of the negative charge of electrons. But what we can say further is that Thompson was unable to determine how much negative charge and electron possesses. And it wasn't until 1913 where Robert Millikan and harvey fletcher discovered the fundamental charge of an electron. Now here we're going to talk about the Millikan oil drop experiment here, we're going to say that Millikan and fletcher used oil droplets, charged plates, gravity and X rays to determine the amount of charge. And here there are certain things that we need to remember. We have our atomizer. This is just the container used to disperse the individual oil droplets here in this drawing, we can say that this is our atomizer. And what we do here is we would basically drive this atomizer into this opening and basically squeeze on the nozzle And a smith of oil droplets will be sprayed within our apparatus. Next we need to realize that we have something called electric force. This is basically the attractive and repulsive forces between particles based on electric charges. Remember in chemistry, opposite charges attract, we're going to say same charges repel. Now, once we've stuck in this atomizer and basically dispersed our old droplets into the apparatus here we have our oil droplets, these little dots. What happens here is these oil droplets are going to fall through here. This plate. This plate here on top is are positively charged plate. Okay, now, going back to the experiment, the droplets, we say we're introduced to the atomizer, they go through the positive plate here. This is our X ray source. So it's basically going to zap our oil droplets. So the X ray source zaps our oil droplets to give them a negative charge. Here we have our microscope which basically looks at our charged oil droplet, which would be this little dot right here. So here, that's our charged oil droplets. And this blue plate here would just be our negatively charged plate. Now, this box here would be our volt meter which will read the the voltage or charge that could be produced within this experiment. Now here, if we turn on the power of the charge plates, it's gonna create an electric field. And what's important about this electric field is we're going to say that if the voltage is turned up and it becomes greater than the force of gravity, that the drop of itself will rise. But if the voltage is not high enough and it's less than the force of gravity, then the old droplet will fall. What we have to do here is we have to apply the right amount of voltage that will help. If we can do it, help the drop it be suspended in air. And if we could suspend that droplet in air between our positive and negative plates, it's through the suspension that we can figure out the charge of our electron. And that's what they were able to do with this experiment. See through the suspension of the oil dropping, the charge of an electron was determined to be negative 1. times 10 to the -19 columns columns representing charge. Okay, so just realize that when it came to the Millikan oil drop experiment, it helped to further the experiment of Thompson. It helped us to figure out the amount of negative charge on any given electron.

we're told that the fundamental charge of an electron is negative 1.60 times 10 to the negative 19 Cool apps. If a scientist that sermons the charge to mass ratio of an electron is negative 1.76 times 10 to the eight columns program What will be the total mass of an electron? Alright, so for a question like this, they want us to determine the total mass. So that is what our end amount needs to be. So end amount here will be the grams off our electrons and are given amount. Remember, are given amount is when we have ah value that has only one unit connected to it and hear that one unit one unit by itself would be this charge of an electron. So that's are given amount 1.60 times 10 to the negative columns. Remember, don't forget the negative sign now to go from the given amount to the end amount, we have to utilize conversion factors. Remember, conversion factor is when you have two units tied together, our conversion factor here would be negative 1.76 times 10 to the eight columns per gram. Columns and grams are two different units that are being tied together. We need to cancel out columns so we could put the negative 1.76 times 10 to the eight. Coolum is on the bottom, and that's for everyone, Graham. So this would represent our conversion factor and we'd see here that Coolum would cancel out and have as my units at the end grams, which is what I'm looking for. So all we have to say here is this question requires only one conversion factor. So then it's just going to be this value here, divided by this value here and that will give us our grams. Remember, when you have a number written in scientific notation, you need to put it in parentheses. Otherwise, you may get the incorrect answer. If you do this correctly, you'll get approximately 9.10 times 10 to the negative 28 g as a total mass of your electron. So based on that answer, option B would be the correct choice