Electric field lines and Electric dipole

* “ Electric field lines”:

Electric field lines are the smooth curve in an electric field on which unit positive charge moves.

* “Some important general properties of field lines are”:

1). Field lines start from positive charge and end on a negative charge.

2.) Field lines never cross each other if they do so then at the point of intersection there will be two direction of electric field.

3.) Electric field lines do not pass through a conductor , this shows that electric field inside a conductor is always zero.

4.) Electric field lines are continuous curves in a charge free region.



* “Electric Dipole”:
It is the system of two unlike point charges having equal magnitude and they are separated at very short distance.

Electric dipole moment definition :- The dipole moment of an electric field is a vector whose magnitude is charge times the separation between two opposite charges.

• Direction of dipole moment is along the dipole axis from negative charge to positive charge.
• Consider the figure given below which shows an electric dipole consisting of charges $(\pm q)$ separated by a small distance $2a$. 
  

  

  Mathematically,$$\begin{array}{cc}\text{Dipole Moment}=& \text{either one of charges}\times \\ & \text{separation vector from +ive to -ive}\end{array}$$$\vec{p}=q\left(2\vec{a}\right)C.m$ .                                             Above equation gives Electric dipole moment formula
• Magnitude of dipole moment is 
  $|\vec{p}|=q\times 2a$
• The Electric dipole moment direction is from negative charge to positive charge.
• The SI unit of dipole moment is Coulomb-meter
• $(C-m)$
• $$

• Dimensional Formula = [LTA]


Next topic is application of electric field