Electric field, potential

You could understand more easily if you think of simliar situation in mechanics.

In mechanics, a difference in height causes an object to fall freely under gravity. The "height" in mechanics is similar to the "electrical potential" in electrostatics. A difference in electrical potential casues a charge to move.

Electrical potential energy is similar to "gravitational potential energy". Gravitational potential energy is the energy possessed by an object because of its position (i.e. height) from the ground. Electrical potential energy is the energy possessed by a charge because of its position in an electric field.

Hence, gravitational potential energy = (mg)h
(m=mass, g = acceleration due to gravity, h = height)
electricla potential energy = qV
(q = charge, V = electrical potential difference)



Electric field is, in fact, the potential gradient. It gives an indication of how strong is the electrical force that causes a unit charge to move. By definition,

E = -dV/dx

In mechanics, the gravitational potnetial Vg, which is the force per unit mass, is,
Vg = mgh/m = gh

The gravitational field intensity Eg is
Eg = -d(gh)/dh = -g
which is just the acceleration due to gravity. As you know, the acceleration due to gravity measures the strength of the gravitational field. It is different on earth and other planets, e.g. on Mars, Jupiter or on the moon.

Electric field intensity could thus be interpreted in a similar way.