Question

In what way can I intuitively visualize where an electric field is zero?

In particular, I'm thinking of two unequal opposite charges on a line, knowing that the electric field on the line will be zero just to the outside of the smaller charge. How can I visualize this? Perhaps provide a diagram and explain?

Answer 1

Because the electric field is proportional to the charge and inversely proportional to the square of the distance from it, you can see where the field will be zero by compensating the ratio of the charges by the ratio of the squares of the distances. For instance, for your particular case,