Electromotive force (EMF) of the cell.
In this topic we will discuss about what is Electromotive force (EMF) of the cell and it is different from potential difference .
As we know electric current flows through a complete closed circuit ,when there is an source of external force which can bring the ions from low potential to high potential . This external for which makes the current carriers to move in a definite direction called electromotive force (EMF) . In another words we can define ‘ It is the maximum potential difference between two electrodes of the cell when no current flows through the circuits i.e. in open (off) circuit‘ .
Unit of the EMF is Volt (V) and it is generally represented by ‘E’
Difference between EMF of a cell and potential difference –
(i) EMF -It is related with source of current
P.D. – It is related with any two points of the closed circuit.
(ii) EMF – It cause of potential difference between two point of circuit .
P.D. – It is an effect .
(III) EMF – It is the amount of work done in taking a unit charge once round the complete circuit .
P.D. – It is the amount of work done to bring unit charge from one point to another point .
(iv) EMF – It is equal to sum of potential difference across all components of the circuit ( Including all the cells connected in the circuit .
P.D. – In a closed circuit the different components of the circuit have different potential difference .
(v) EMF – It is independent of the external resistance and current drawn from the circuit .
P.D. – It depends on the resistance between two points of circuit and current flowing through it .