In the circuit - ' TO COMPARE THE EMF OF TWO CELLS USING POTENTIOMETER ' . suppose the battery is connected to ' A ' end of potentiometer , let a null deflection be obtained in galvanometer at point ' J ' . . at that state why the emf of cell becomes equal to the potential difference between the points ' A ' and ' J ' ?
how TO COMPARE THE EMF OF TWO CELLS USING POTENTIOMETER