# Electric Field Lines by A.K.Sinha

Electric field lines & their properties :

Electric Field Lines :

Electric field lines or electric lines of force are imaginary lines which are used to show the direction of electric field intensity at a particular point around a source charge.

we may define an electric field line as a path, straight or curved such that tangent to it at any point gives the direction of electric field intensity at that point.

( Concept :

FIG. 1

In above figure AB is an electric line of force. The tangent to the line at any point P gives us the direction of electric intensity EP at P. Similarly, tangent to AB at Q gives us the direction of EQ .

Properties of electric field lines :

• Start from positive charge and end to negative charge.

FIG : Observe the direction of arrows

• Perpendicular to the surface of conductor. Electric field lines are always perpendicular to the surface of any charge conductor.

• Intersect Never to each other. Because at the point of intersection there are two direction of electric intensity at the same point( as shown in fig. ) which is not possible.

• Tangent to the curve at any point gives the direction of electric field intensity at that point ( see point P & Q in FIG. 1 ).

• Intensity of field is maximum when charges are closely packed and minimum when loosely packed.

• Contract longitudinally : The electric field lines contract longitudinally to show attraction between unlike charges.

• Exert lateral pressure : The electric field lines exert lateral pressure which show repulsion between like charges.

( NOTE :  You can remember all the 7 properties by using words SPIT ICE as a trick. See the first bold letter of all 7 properties )