1 00:00:000,100 00:00:07,840 This electric potential V, has units of volts. Okay, that's the SI unit for electric potential V. W, which was work We said is equal to negative Q Delta V. And Q is of course charge. So that has units of coulombs. Volts is the SI unit. And so a coulomb volt is also energy. Right, work has the same units as energy. But Q, you don't have to write in coulombs There's another way to write it which is E times V. And this is electron volts. Okay, the SI unit is coulombs times volts but we often talk about electron volts and you've probably heard electron volts before particularly in your chemistry classes when they talk about what's the ionization energy of a certain atom they will say, oh it is six electron volts or thirteen point six electron volts. That is a unit of energy. That says how much energy do you have to apply to the system to strip the electron off. So one electron volt means the following: The energy acquired by an electron accelerating through one volt Okay. That's what one electron volt means. You're going to take the electron, you're going to accelerate it through a potential difference of one volt, that's how much energy it requires. It acquires one electron volt. Okay, so there's all this relationship between energy and electric field and electric potential V, and those relationships we can take advantage of. So let's take a look at one of your homework problems and this is I believe it's number seventeen point zero five, okay, and let's take a look and see if we can make some sense of that.