The e.m.f. is that force that sources the flow of current in the given circuit; allow us to perceive its which means a lot of clearly.
Think through an easy cell shown in Fig. Owed to the chemical reaction in the solution the terminal 'A' has attained positive charge whereas terminal 'B' has attained negative charge.
Now a bit of conductor is joined amongst the terminals A and B then drift of electrons starts through it. This can be nothing however the movement of current through the conductor. This can also be shown in the Fig. The electrons can drift from terminal B to A and hence the path of current is from A to B i.e, positive to negative as shown.
One might suppose that after the positive charge on terminal A gets neutral due to the electrons, then flow of electrons can stop. Each the terminals might get neutral once some time. However this will not happen much. This can be as a result of chemical change in the solution maintains terminal A absolutely charged and terminal B as negatively charged. This keeps the drift of current; the chemical change converts chemical energy into electrical energy that maintains flow of electrons.
Consider 2 points P and Q as shown within the Fig-b, then this is flowing from point P to Q. this suggests there exists a potential difference between the points P and Q. This potential difference is termed voltage denoted as V and, measured in volts.
Difference between the e.m.f. and potential difference as below:
Within the cell 2 energy transformations are taking place at the same time. The one is chemical energy as a result of resolution in cell is obtaining reborn to electrical energy that is basic cause for flow of electrons and hence current. The succeeding is once current flows, the portion of metal gets heated up i.e, electrical energy is obtaining reborn to heat energy, due to flow of current.
In the 1st transformation' electrical energy is produced from different kind of energy. The force involved in such transformation is electromotive force. Once current flows, owing to that metal get heated up i.e, due to presence of potential difference between 2 points, voltage is existing. And in such case electrical energy gets reborn to different style of energy. The force concerned in such transformation 'is nothing however the potential difference or voltage. Both e.m.f. and potential difference are in typically referred as voltage.