I'm studying electrostatics, then I read the concept of electric potential and potential difference. They said "the electric potential at a point in the given electric field is defined as the work done in moving per unit positive charge from infinity to that point against electrostatic forces of attraction of the source charge irrespective of the path followed." I did not understand what is this work done from infinity and the concept of potential difference. Clearly saying I did not understand both concepts of potential difference and electric potential? Please clear my concepts and tell me what is this work done?
I did not understand what is this work done from infinity and concept of potential difference .
There is an electric field. In order to move a charged particle around in this field you will have to exert a force on the particle. If you exert a force on a particle as it moves, you're doing work on the particle.
Possibly, the electric field will be pulling the particle the way you want it to move. Then you'll have to exert a force in the opposite direction to make sure it moves quasi-statically. The particle will be doing work on you (or you're doing negative work on the particle).
Well don't know how accurate I may sound here. Electric potential From infinity in my own understanding might be the work done in taking a unit test charge (although not necessarily positive, for point of convenience positive charge is always used) from an unknown point to a known point. So taking a test charge from an arbitrary infinite point to a known point needs some forces. The product of the force you applied and the distance you covered gives you the work you have done.