Question

A potentiometer can measure emf of a cell because
(A) the sensitivity of potentiometer is large.
(B) no current is drawn from the cell at balance.
(C) no current flows in the wire of potentiometer at balance.
(D) internal resistance of cell is neglected.​

Answer 1

Answer:

(B) no current is drawn from the cell at balance.

Answer 2

A potentiometer can measure the emf of a cell because no current is drawn from the cell at balance.

Working Principle:

A potentiometer works on the principle that no current is drawn from the cell at the balance point. It acts as an open circuit and the galvanometer reading is zero.

This property makes a potentiometer more sensitive than a voltmeter.

Applications of a Potentiometer:

A potentiometer can be used for:

1. Finding the EMF of an unknown cell
2. Comparing EMF of any two cells with unknown EMF
3. Finding the internal resistance of a cell