Why is potentiometer converted for the measurement of emf of a cell? Explain.

Why is potentiometer preferred to voltmeter for the measurement of emf of a cell? Explain.

Where does the emf of a cell exist?

Explain the principle on which the working of a potentiometre is based. Why is the use of a potentiometer preferred over that of a voltmeter for measurement of e.m.f. of a cell?

Statement I : a potentimeter arrangement is more suitable than a voltmeter arrangement for the accurate measurement of the emf of an electric cell . Statement II : It is possible to connect an electric cell in a potentimeter circuit in such a way that no current passes through the cell .

Define standard emf of a cell.