What does 0 electric potential difference mean?

[kyub7]

This isn't a homework question, but while working on some questions in Physics AP C, I've come across several questions involving 0 PD (potential difference).
My question is simple; what does 0 PD mean?
so far i know that 0 potential difference of any kind is arbitrary, since it represents the amount of energy required to displace it from point a to b. Therefore i am aware that 0 does not really mean: 'no potential energy at that point'.

(new to forum; i hope there's an image above this line^^)

the image above is a simulation of 1 negative charge, and 3 positive charge with some distance between them. the white area supposedly shows 0 PD, but what is so special about it? Does a charge or an object behave differently in those areas?

 

[arildno]

0 potential value is arbitrary; 0 potential difference is not.

0 potential difference between two locations means that the potential values AT each point are the same.

As to your specific question:
What would be the effective force on a charged particle placed within the white region?

 

[BiGyElLoWhAt]

As arildno stated, you're not being consistent with use of your termonology.
$U_{q}="Electric Potential"$
$V= "Potential Difference" = U_{q_{f}}-U_{q_{o}}$
The second is what you measure with your ammeter in class.

 

[BiGyElLoWhAt]

To actually answer your question, 0 electric potential is like setting a 0 for gravitational potential energy, put it where it's most convenient (probably ground in your circuit)
0 Potential difference means that the 2 points your measuring between are at the same electric potential.