project to study various factors on which the internal resistance emf of a cell depends
Potential difference between the two poles of the cell in an open circuit is calledemfof the cell.
SI unit is volt (V).Internal resistance (r) of cell
Resistance offered by the electrolyte of the cell when the electric current flows through it
r Internal resistance of the cell
R External resistance
The keyKis closed and a currentIflows in the circuit.
According toOhms law,
LetVbe the terminal potential difference. The terminal potential difference V is less thanemfE of the cell by an equal amount, which is equal to potential drop across external resistance R i.e.,
Also, terminal potential difference is equal to potential differences across external resistance.
From equation (1),