Chapter 16, Problem 20Q

Why can electric field lines never cross?

To determine

Why electric field lines never intersect.

Answer to Problem 20Q

Solution:

Two field lines cannot intersect each other since the field at the point of intersection will not have a unique direction.

Explanation of Solution

The tangent drawn at any point on an electric field line represents the direction of net electric field at that point. If two electric field lines intersect at a certain point we can draw two tangents at that point indicating two directions for electric field at the same point which is impossible. That is why two electric field lines can never cross each other.