The amount of energy supplied by the source to each coulomb of charge is known as emf of the source, whereas the amount of energy used by one coulomb of charge in moving from one point to the other is known as potential difference between the two points.
For instant, consider a circuit as shown in Figure 1.7. If a battery has an emf of 12 V,it means that the battery supplies 12 joule of energy to each coulomb of charge continuously. When each coulomb of charge travels from positive terminal to negative terminal through external circuit, it gives up whole of the energy originally supplied by the battery.
Fig. 1.7 Electric circuit to represent emf and potential difference
The potential difference between any two points, say A and B, is the energy used by one coulomb of charge in moving from one point (A) to the other (B). Therefore, potential difference between points A and B is 7 V.
Leave a Reply