Question about Electric Field Strength and Electric Potential

[Steven7]

Lets say I have a point charge X placed on a region between a +Q test charge and +2Q point charge where electric field strength is zero. Since E=-dV/dR, does it mean V=0 or constant? Can the point charge move if i place it there? Well let's just ignore gravitational field/force here.

 

[Doc Al]

Since E=-dV/dR, does it mean V=0 or constant?

No, V ≠ 0. But the rate of change of V with respect to R is zero. That means the potential is a minimum at that point.

Can the point charge move if i place it there?

Why would it move? Is there a force on it?