Equipotentials for Dipoles
Description:
Let there be a dipole. The start and termination of electric field lines is shown in figure. The concentration of Electric field is more at the middle of two charges as the distance is minimum in between charges . As the distance between the points on the charge increases , the concentration of Electric field decreases. So, it is less at rest of the areas around dipole.
We know, dV = Edr
If we take equal dV, Electric field becomes weaker and dr will be larger i.e Where-ever there is weaker electric field, the equipotential passes through larger distance.
Shape of equipotential in a dipole
In between the dipole, the equipotential surface around each charge is closer to the charge whereas, equipotential moves through a greater distance from charge where electric field is weaker. As shown in fig. Unconditionally, equipotential remains perpendicular to the electric field. At the centre of dipole ( anywhere at equatorial), where the potential is zero, there will be no equipotential. Or we can say, that there exists an equipotential at the centre of dipole, which is like a straight line having zero potential.
Shape of equipotential in case of two similar charges
Let there be a system of two positive charges. The directions of Electric field lines is as shown in figure. The equipotential surface around both the charge will always be perpendicular to the electric field. As the electric field experiences repulsion at the centre, so the equipotential surfaces at centre is as shown in figure.
V1 > V2 > V3
From very far distance, both the charges appear to be very close. Hence all the distances near to any of the charge appears to be equidistant. So ,the equipotential of the system appears as shown in figure.
