Internal resistance of a cell
The opposition offered by the cell's electrolyte to the flow of electric current through it is called internal resistance of the cell.
Factors affecting the internal resistance of a cell:
I) The greater the separation between the electrodes of the cell, the longer the electrolyte through which the current has to flow and, consequently, a higher value of the internal resistance
Ii) The higher the conductivity of the electrolyte, the lower the internal resistance of the cell. That is, the internal resistance depends on the nature of the electrolyte.
Iii) The internal resistance of a cell is inversely proportional to the common area of the electrodes that immerse in the electrolyte.
Iv) The internal resistance of a cell depends on the nature of the electrodes. RE rI IE = V + v= IR + Ir= I (R + r) I = E / (R + r) .This relationship is called the circuit equation.