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# What are electric field lines? electric force line

Hello friends in this article we will know that electric field What are electric force lines? What are the properties of electric field lines? What is electric intensity or field strength? What is flux density and electric flux? And learn about many facts related to it.

## Properties of electric field lines. property of electric force line

Electric field lines have the following properties:

1. Electric field lines are directed away from the positive charge and towards the negative charge so that at any point, the tangent to a field line gives the direction of the electric field at that point.
2. Electric lines of force start with a positive charge and end at a negative charge.
3. Electric lines of force normally leave or enter from a charged surface.
4. Electric lines of force cannot pass through a conductor. This means that the electric field inside a conductor is zero.
5. Electric lines of force never intersect, so if two electric lines of force intersect at a point (such as point P in Figure 5.5), then two tangents can be drawn at that point. This would mean two directions of the electric field at that point which are impossible.
6. Electric lines of force have a tendency to contract in length. This explains the attraction between oppositely charged bodies.
7. Electric force lines have a tendency to extend laterally, that is, they tend to separate one from the cache in a direction perpendicular to their length. This explains the repulsion between equal charges.

## electric intensity or field strength

In order to describe an electric field, we have to specify its intensity or strength, the intensity of the ditric field at any point is determined by the force acting on a unit positive charge applied at that point. The electric intensity (or field strength) at a point in an electric field is the force acting on a positive charge placed at that point. Its direction is the direction along which the force acts, the electric intensity at a point,

E = F/+Q N/C

Where, Q = charge in Coulomb placed at that point and F = Q is force in Newton acting on Coulomb.

If a 2 coulomb charge at a point in an electric field experiences a force of 10 N, then the electric intensity at that point will be 10/2 = 5 N/C. The following points may be observed carefully:-

1. D Since electric intensity is a force, it is a vector quantity that has both magnitude and direction.
2. Electric intensity can also be described as lines of force. Where the lines of force are close to each other, the intensity is high and where the lines of force are widely separated, the intensity is low.
3. Electric intensity can also be expressed in V/m. And 1 V/m = 1 N/C

## Electric Flux and Flux Density

In addition to electric fields, we commonly use the term electric flux (denoted by the symbol y) in place of power to power lines. Electric current is measured in coulombs. Thus a body charged with Q coulomb emits a total electric current of Q coulomb.

i.e. electric flux = Q coulomb

Electric flux density is defined as the electric flux that normally passes through a unit area. Thus, if the electric flux of Q Coulomb is passing normally through the region A m²,

So the electric flux density, D = Electric flux/A = Q/AC/m² and the ratio D/E is equal to the absolute permittivity (ɛ) i.e. D/E = or D = E =0 ?r E