Fri April 22, 2011 By: Gaurav Avhad

what is potential at a particular point in space why there must be a difference in potential so that charges flow has emf to do with it at all?

Expert Reply
Fri April 29, 2011
Potential at a particular point in space is defined as the work done in bringing a unit positive charge from infinity to that point. For charges to flow from one point to the other, there must be a difference in potential at the two points as charges are only capable of flowing from a point at higher potential to a point at lower potential. For two points at same potential, no net charge flow takes place and exchange of charges is in equilibrium.
A difference in charge between two points in a material can be created by an external energy source such as a battery. This causes electrons to move so that there is an excess of electrons at one point and a deficiency of electrons at a second point. This difference in charge is stored as electrical potential energy known as emf.
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