What is an Electric Force?
It works the same way for a negative charge, you also have an electric field around it. Now, like charges repel each other and opposite charges attract. Say you had a positive charge here and a positive charge here, they’re going to repel each other because they are like charges. Then also if you had two negative charges, they’re like charges, so they’re going to repel each other.
Then say you had a positive charge over here and a negative charge over here, they’re going to attract each other, so they’re going to be attracted to one another because they’re opposite charges and opposite charges attract. Now we have lines of force, which show the paths of charges. Say you had a positive charge right here; you would have lines of force coming off of it.
Now, all the lines are going to have arrows on them, so the direction of a positive charge is away from it, and the direction of a negative charge is towards it. All these arrows right here would point away from the positive charge, but if we had a negative charge then all the arrows would point towards it. Then notice here that I drew the arrows on the end of the line, but sometimes the lines will be longer and the arrows will look kind of like that and they’ll just be in the middle of the line, and it works the same way with negative charges, so these arrows are going to point towards the negative charge.
Now electric charge is measured with the unit coulomb and it is spelled like this c o u l o m b, and we can abbreviate it just with a capital C like that. 1 coulomb is equal to what we can say is 1A times 1s. A here stands for amp, and s stands for second, so it’s the amount of charge moved in 1 second by a steady current of 1 amp.
Now, electric force is directly proportional to the product of the charge magnitudes, (so electric force is directly proportional to the product of the charge magnitudes) and then it’s going to be inversely proportional to the distance between the two objects. We’re going to go back up here where it says electric force is directly proportional to the product of the charge magnitudes.
This makes sense, the larger the magnitudes of these charges the more force they’re going to have, so as the magnitudes get higher, the product of both of them combined is going to get higher because we’re looking at two charges here, so we’re going to multiply the two magnitudes together to get a product and so as that goes up, the electric force is going to go up.
Now, the electric force is inversely proportional to the distance between the two objects, so the farther apart the two objects are, the smaller the electric force is going to be because as they’re farther apart they have less of an impact on each other, so we say they’re inversely proportional because as the distance goes up electric force goes down, but as electric force goes up then the distance goes down. When we say up here that electric force is directly proportional, that means when one goes up the other one goes up, and when one goes down the other one goes down. That’s a look at electric force.