Verify this result by placing the test charge on the y$-$axis and viewing the value of the electric potential that the simulation predicts.

Does this mean that the electric field is also zero at these points, since the electric potential can be calculated from the electric field?

Yes, at every point where the potential is zero the electric field must also be zero.

Although V is zero at all points on the y$-$axis, the magnitude of the electric field is not zero at these points. The potential V can be zero while the field strength $|$vector E$|$ is non$-$zero because the field depends on the change in potential, rather than the value of potential itself.

No$.$ However, this is true only because of the choice of a zero of the potential at the origin in this simulation. Notice that the potential is not zero infinitely far from the charges as is the usual choice for the zero of potential.

Yes. However, this is true only because of the choice of a zero of the potential at the origin in this simulation. Notice that the potential is not zero infinitely far from the charges as is the usual choice for the zero of potential.