Electric Field and Potential in Two Dimensions
In this simulation, you can explore the concepts of the electric field
and the electric potential, in a twodimensional situation. You can turn
on 1 to 5 charged particles, and move a test charge around the plane
near these charged particles to sample both the electric field and the
electric potential, produced by the charged particles, at various
points. You can also turn on a grid of field vectors, which show the
direction and, qualitatively, the magnitude of the field at a grid of
equally spaced points in the plane in which the charged particles are
located.
Here are some facts about the electric field from point charges:

the magnitude of the electric field (E) produced by a point charge
with a charge of magnitude Q, at a point a distance r away from the
point charge, is given by the equation E = kQ/r^{2}, where k
is a constant with a value of 8.99 x 10^{9} N m^{2}/C^{2}.

the direction of the electric field produced by a point charge is away
from the charge if the charge is positive, and toward the charge if
the charge is negative.

electric field is a vector, so when there are multiple point charges
present, the net electric field at any point is the vector sum of the
electric fields due to the individual charges.
Here are some facts about the electric potential from point charge

the electric potential (V) produced by a point charge with a charge of
magnitude Q, at a point a distance r away from the point charge, is
given by the equation: V = kQ/r, where k is a constant with a value of
8.99 x 10^{9} N m^{2}/.

electric potential is a scalar, so when there are multiple point
charges present, the net electric potential at any point is the sum of
the electric potentials due to the individual charges.