# Homework Help: When is the Electric Potential 0

1. Jul 15, 2015

### Katran0595

1. The problem statement, all variables and given/known data
The question asks: Where is the electric potential 0?

2. Relevant equations
I believe the relevant equations are v=1/(4*pi*epsilon) (Q/r) or v=-Ed
3. The attempt at a solution
I think that the electric potential is 0 when the electric field is zero as well. However, im not quite sure which equations to look at exactly or if an equation is necessary. Some answers state that the electric potential is zero when it is near the smaller charge or it is zero when the point is at infinity.

2. Jul 15, 2015

### Staff: Mentor

Welcome to the PF.

Is there a figure that goes along with this question? Can you scan it or describe it?

3. Jul 15, 2015

### Katran0595

Unfortunately there is no figure. The professor just asked us the general question :(

4. Jul 16, 2015

### haruspex

It is nothing to do with the field's being zero. Where the field is zero, that just means the potential is not changing there, in any direction.
Potential, whether electric or gravitational, is a relative matter. That is why we usually speak of potential difference. You can set any point to be at zero potential, and determine potentials elsewhere in relation to it. In particular, when we say that some conductor is grounded, we just mean that it is held at the potential we are defining as zero.
That said, a usual convention is to say that the potential at infinity is zero.

5. Jul 16, 2015

### HallsofIvy

"Potential energy" is always relative to some given point. You can choose the potential energy to be 0 at any given point by choosing to calculate it relative to that point.