why it is not corect to say that potential difference is the work done in moving unit charge between the points concerned?

Question

anonymous · Answer

That is Electric Potential Energy, which is work done by a net external force in bringing a charge to that point. 
Potential Difference is defined as the amount of electrical energy (provided by battery that is flowing in the circuit) converted to other forms of energy (when passing through the components of circuit, lets say a bulb, elect. energy is converted to light n heat) per unit charge flow between the points concerned.