Electric lines of force, also known as electric field lines or simply electric field lines, are a conceptual tool used to represent the electric field around charged objects. They help us visualize the direction and strength of the electric field at different points in space. Here are the key properties of electric lines of force:
Start and End at Charges: Electric field lines originate from positive charges and terminate on negative charges. They never start or end in the middle of space, indicating the continuous nature of electric fields.
Tangential to the Field: Electric field lines are always tangent to the electric field vector at any given point. This means that the direction of the electric field at a point is the same as the direction of the electric field line passing through that point.
Perpendicular to Surfaces: Electric field lines are perpendicular to the surface of a conductor in electrostatic equilibrium. This is because the electric field inside a conductor in equilibrium is zero, and charges reside on the surface. Therefore, the electric field lines entering or leaving a conductor's surface must be perpendicular.
Closer Lines Indicate Stronger Field: The density of electric field lines in a given region represents the strength of the electric field. When the lines are closer together, it indicates a stronger electric field, and when they are farther apart, the field is weaker.
Never Cross Each Other: Electric field lines never intersect or cross each other. If they were to cross, it would imply that at the point of intersection, there would be multiple directions for the electric field, which is physically unrealistic.
Uniform Field: In a uniform electric field between two parallel charged plates, the field lines are straight and equidistant from each other. This indicates a constant electric field strength.
Curvature Near Charges: Around a point charge, the electric field lines are curved, radially extending outward from the charge in all directions. The curvature indicates the changing strength of the electric field with distance from the charge.
Continuous Path: Electric field lines provide a continuous path from one charged object to another, showing how the electric field connects charges in space.
Indication of Field Direction: The direction of the electric field at any point is given by the direction of the electric field line passing through that point. If an observer follows the path of an electric field line, they would move in the direction of the electric field.
No Closed Loops (in Electrostatics): In electrostatics (when charges are not moving), electric field lines do not form closed loops. This is because there are no sources or sinks of electric field (like magnetic monopoles in magnetism) in electrostatics.
Electric field lines are a useful visualization tool to understand the behavior of electric fields and their interactions with charges and objects in space. They help convey important information about the nature and distribution of electric fields in a simple and intuitive manner.