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What is an electric field | Electric field lines | Properties of electric lines of forces | Basic electrical

In this article, we both will discuss what is the electric field and electric field lines definition and the properties of electric lines of forces.


 ELECTRIC FIELD

The electrostatic force acts between two charged bodies even without any direct contact between them. The nature of this action at distance force can be understood by introducing the concept of the electric field.


Consider a charged body carrying a positive charge q placed at a point O. It is assumed that the charged q produces an electrical environment in the surrounding space, called an electric field.


Electric Field 

An electric field is said to exist at a point if a force of electrical origin is exerted on a stationary charged body placed at that point. Quantitatively, the electric field or the electric intensity or the electric field strength E at a point is defined as the force experienced by a unit positive test charge placed at that point, without disturbing the position of the source charge.

 In simple words, you can say that the electric field at a point is defined as the electrostatic force per unit test charge acting on a vanishingly small positive test charge placed at that point.

Hence , Ē=limƑ/q0


The electric field Ä’ is a vector quantity whose direction is the same as the force F exerted on a positive test charge.


UNIT and DIMENSIONS of electric field 


As the electric field is force per unit charge, its SI unit is Newton per coulomb(N/C). It is equivalent to volt per meter(V/m).


The dimensions for Ä’ can be determined as follow :

[E]=Force/charge=MLT-2/C

    = MLT-2/A*T   =[MLT-3A-1]


What are electric lines of forces? 


The concept of field lines was introduced by Michael Faraday as an aid in visualizing electric and magnetic fields. In simple words 

Electric lines of forces are an imaginary straight or curved path along which a unit positive charge tends to move in an electric field.


Properties of electric lines of forces :

  1. The lines of forces are continuous smooth curves without any breaks.

  2. The tangent to a line of force at any point gives the direction of the electric field at that point.

  3. The line of forces starts at positive charges and ends at negative charges, they cannot form closed loops. If there is a single charge, then the lines of forces will start or end at infinity.

  4. Electric lines of forces obey inverse square law.

  5. Electric lines of force are continuous in nature.

  6. No two lines of forces can cross each other.

  7. Electric lines of forces due to a positive point charge is always direct radially outwards and those due to the negative point charge are always direct radially inwards.

  8. Electric lines of forces exert a lateral pressure due to the force of repulsion between two similar charges.

  9. Electric lines of forces contract longitudinally due to the force of attraction between two opposite charges.

  10. The lines of force are always normal to the surface of a conductor which the charge is in equilibrium.

  11. The line of forces has a tendency to contract lengthwise. This explains attraction between two, unlike charges.

  12. The lines of forces do not pass through a conductor because the electric field inside a charged conductor is zero.
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