Electromotive force and internal resistance

Although electrons move quite freely in wires, they do not flow in one direction unless they are connected to a cell or some other source of energy. Consider an ordinary dry cell as a source of electrical energy. A chemical reaction occurs in the dry cell that results in a potential difference is produced between the positive and negative terminals. If a current path is provided then current can flow throughout the circuit. As the electrons move around the circuit, they transfer their energy to the bulb and the connecting wires.

When the electrons reach the cell again after flowing around the circuit, they would have lost almost all their initial potential energy. Energy is transferred to the electrons from the chemical reaction that takes place inside the cell. The electrons gain potential energy and the process is repeated.

The electromotive force (e.m.f) is defined as the work done by a source in driving one coulomb of charge around a complete circuit.

The unit of e.m.f is the volt, V which is equivalent to J C-1

1 comment:

Electron Configuration Chart said...

Thanks for providing information on emf which is responsible for conduction of electrons in the conductor.