i. Consider a resistor AB connected to a cell in a circuit with current flowing from A to B.
ii. The cell maintains a potential difference V between the two terminals of the resistor, higher potential at A and lower at B.
iii. Let Q be the charge flowing in time ∆t through the resistor from A to B.
iv. The potential difference V between the two points A and B, is equal to the amount of work (W) done to carry a unit positive charge from A to B.
∴ V = \(\frac{W}{Q}\)
v. The cell provides this energy through the charge Q, to the resistor AB where the work is performed.
vi. When the charge Q flows from the higher potential point A to the lower potential point B, there is decrease in its potential energy by an amount ∆U = QV = I∆tV
where I is current due to the charge Q flowing in time ∆t.
