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Electrons - Quantization of Electric Charge

Teacher/Instructor Jonathan Osbourne
Jonathan Osbourne

PhD., University of Maryland
Published author

Jonathan is a published author and recently completed a book on physics and applied mathematics.

Electric charge is the transfer of electrons from one material to another. So negative charge means that there is an excess of electrons while positive charge is a deficiency of electrons. Quantization of charge means that when we say something has a given charge, we mean that that is how many times the charge of a single electron it has. Because all charges are associated with a whole electron, this is possible.

Let's talk about electrons and quantization of electric charge. Now way long ago when people were first discovering electrofaction they had no idea what was causing it. But later experiments at the end of the 19th century showed that electric charge in ordinary materials is accomplished by the transfer of electrons. So there is a certain type of particle that will be transferred from one object to another when we have charging going on.

Alright. So electrons have a a negative charge, negative charge. And that means that when I rub silk on glass, the glass gets a positive charge. Well, how does it do that? Now people might think the silk gives up protons to the glass but that's not what happens. Protons stay where they are. Wherever the protons are, that's where the silk is. Alright. So the silk isn't giving itself up to the glass. So instead of that this silk strips electrons away from the glass. So that means that the glass has less electrons, still got the same number of protons, so that means that now it has a positive charge. And that's something that sometimes is confusing to people especially since you know that there's all these protons business, right? And they've got positive charge. So you think well, jeez, if you've got positive charge you got too many protons. But that's not the way that it works. It means you have too few electrons.

Now, along the same lines, if you rubbed fur on amber, the amber's going to get a negative charge. And that means that fur is giving its electrons up to the amber. So now, whenever you have a negative charge, it means you have too many electrons. Whenever you've got a positive charge it means you've got too few electrons. And that's a very important thing for you to understand how that works. It's not the protons that are moving, it's always the electrons. Whether it's a positive charge or a negative charge, always the electrons that are moving.

Alright. Now, the electron charge is -1.6 times 10 to the -19 coulombs. And since all these charge transfers are associated with transfers of electrons, it means that all charges that you can get on an object must be a multiple of this number right here. So 2 times 10 to the -19 coulombs is not possible, you cannot have that charge on anything. It doesn't matter. Even if the material's not ordinary, you cannot have 2 times 10 to the -19 coulombs. What about 3.2 times 10 to the -19 coulombs? Well, that's just 2 times this with a negative sign. So that means that 3.2 times 10 to the -19 coulombs is associated with an object that is missing 2 electrons. Alright.

What about -8 times 10 to the -19 coulombs? Well, 8 is 5 times 1.6. So that means that if I've got -8 times 10 to the -19 coulombs, I've got 5 electrons too many. So that's the idea. Should always remember 1.6 times 10 to the -19 and everybody got to be a multiple of that. t's not a multiple of that, not possible.

And that's electrons and quantization.