Volymeter can not be used to measure emf to a cell potentiometer can be used to measure emf of a cell because

A potentiometer can be used to measure

How do you measure the Emf of a cell

(A): Potentiometer is much better than a Voltmeter for measuring emf of cell (R): A potentiometer draws no current while measuirng emf of a cell at balancing point.

Instrument used to measure e.m.f of the cell accurately is