Difference between
e.m.f and potential difference 12th class
Answers
EMF of a cell 1. The EMF of a cell is the maximum potential difference between the two electrodes of a cell when the cell is the open circuit. 2. EMF is independent of resistance of circuit and depends upon the nature of electrodes and electrolyte. 3. The term EMF is used for source of current. 4. It is a cause. Potential difference 1. The potential difference between the two points is the difference of potential between these two points in a closed circuit. 2. This depends upon the resistance between two points in a circuit and current flowing through the circuit. 3. Potential difference can be measured between any two points of circuit. 4. It is an effect.
Answer :
Potential difference and e.m.f. :
The potential difference is the difference between the electrode potentials of the two electrodes of the cell under any condition. On the other hand, e.m.f. is the potential generated by the cell when it does not draw any current. The important points are given as follows :
- E.M.F. is the potential difference between the two electrodes when no current is flowing in the circuit i.e., in an open circuit.
- Potential difference is the difference of the electrode potentials of the two electrodes when the cell is sending current through the circuit.
- E.M.F. is the maximum voltage obtainable from the cell.
- Potential difference is less than the maximum voltage obtainable from the cell (i.e., E.M.F. if the cell).
- E.M.F. is responsible for the flow of steady current in the cell.
- Potential difference is not responsible for the flow of steady current in the cell.