Electric Potential Energy question

[th3plan]

This isn't really a homework problem. I just want to understand electric potention
$$\Delta$$V=Uf-Ui=-W

Uf= final
Ui=initial

Can someone explain to me how electric potential acts between two positive electrons, or two negative electrons or a + and a negative electron. In which cases would work be positive and why ?

Thank you

 

[tiny-tim]

Can someone explain to me how electric potential acts between two positive electrons, or two negative electrons or a + and a negative electron. In which cases would work be positive and why ?

Hi th3plan!

We (arbitrarily) define the potential to be 0 at infinite distance.

To bring a + charge near another + from infinity, you have to overcome the repulsion, so you have to do work on it.

To bring a - charge near a + to infinity, you have to overcome the attraction, so you have to do work on it.

 

[th3plan]

so if work has to be done on it its considered -w , for a + to a + to be brought together, but for a + and a - u have to do work to bring together ? Why ? They naturally attract :S ?

 

[tiny-tim]

so if work has to be done on it its considered -w , for a + to a + to be brought together, but for a + and a - u have to do work to bring together ? Why ? They naturally attract :S ?

Hi th3plan!

No, you have to do work to separate them, to bring them to infinity.

 

[tiny-tim]

Hi th3plan! Thanks for the PM.

kinda still confused. Let's say the potential given to me is positive and something like 200V. This means the electric field is in the same directions as potential ?

(Assuming the potential at infinity is 0?)

The electric field points outward for a same charge, and inward for an opposite charge.