Thursday, January 29, 2015

Electric Lines Of Force

An electric line of force is defined as the path traced by a test charge when placed in the electric field.

According to coulomb's Laws, a positive charge repels a positive charge and attracts a negative charge, therefore, an electric line of force always starts from the positive charge and ends on the negative charge.
                   

Properties of electric lines of force :Following are the important properties of electric lines of force :

1. An electric line of force starts from the positive charge and ends on the negative charge.

2. An electric line of force does not form a closed loop like a magnetic line of force. There is no electric field inside a charged body and, therefore, the electric line of force ends on the negative charge.
                                 dipole.gif (3504 bytes)
3. Two electric lines of force never cross each other. The crossing of two lines of force means that there are two directions of the force on a test charge at a point which is impossible.It is well known that a body can move in one and only one direction under the action of force. Hence two electric lines of force can never cross each other.

4. The electric lines of force in the same direction repel each other and those in the opposite direction attract each other.
                                 
5. The tendency of electric lines of force is to taken easy electric path.


Thus, if hollow conductor is placed in the electric field, the electric lines of force will continue their paths through the conducting material. 
The path of lines of force will be through the material of the conductor and not through the hollow space. 
It is because the conducting material provides an easy path due to its high permittivity, whereas air has low permittivity and hence the electric lines of force reject the path through it.

This explains that if a hollow conductor is placed in the electric field or there is charge on its surface, the electric field inside the hollow conductor is zero.

Courtesy:Physics.bu.edu   
labman.phys.utk.edu

No comments:

Post a Comment