Question

Why do we prefer potentiometer to compare the e.m.f of cells than the voltmeter. Why?

Answer 1

The terminal voltage of a cell is the potential difference between its electrodes. A voltmeter cannot be used to measure the emf of a cell because a voltmeter draws some current from the cell. To measure a cell's emf a potentiometer is used since in a potentiometer measurement no current is flowing

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Answer 2

The terminal voltage of a cell is the potential difference between its electrodes. A voltmeter cannot be used to measure the emf of a cell because avoltmeter draws some current from thecell. To measure a cell's emf apotentiometer is used since in apotentiometer measurement no currentis flowing.