Potential difference between any two points is defined as the amount of work done in moving a unit charge from one point to another
The potential difference between points A and B, VB-VA, is defined as the shift in the potential energy of a charge q, divided by the charge, shifted from A to B. Joules per coulomb, given the term volt (V) after Alessandro Volta, are units of potential difference.
If a positive charge is moved from a point at a higher potential to a point at a lower potential energy is liberated.
In actual practice electric charge moves from lower potential to higher potential here there is a loss of energy by electrons moving from lower potential to higher potential the loss of energy appears as heat.
Unit of potential difference
The unit of potential difference is volt.