What is meant by electromotive force ?

Explanation

(i) The emf of a battery or cell is the voltage provided by the battery whenno current flows in the external circuit.
(ii) Electromotive force determines the amount of work a battery or cell does to move a certain amount of charge around the circuit. it is denoted by the symbol `xi` and to be pronounced as 'xi'. An ideal battery has zero internal resistance and the potential difference (terminal voltage) across the battery equals to its emf.
(iii) A real battery is made of electrodes and electrolyte, there is resistance to the flow of charges within the battery. This resistance is called internal resistance r. for a real battery, the terminal voltage is not equal to the emf of the battery. a freshly preparred c cell low internal resistance and it increases with ageing.