Today we will discuss electric lines of forces and their properties.
Definition of Electric line of force: An electric line of force is a path, straight or curved, such that tangent to it at any point gives the direction of electric field intensity at that point.
In Fig. 1, PQ is an electrostatic line of force. The tangent to the line at any point A gives the direction of electric intensity EA at A. Similarly, tangent to PQ at B gives the direction of EB, (see Figure)
Let us discuss the direction of electric field lines for different types of charges: