Question
Potentiometer measures the potential difference more accurately than a voltmeter, because
A.
it has a wire of high resistance
B.
it has a wire of low resistance
C.
it does not draw current from external circuit
D.
it draws a heavy current from external circuit
Answer :
it does not draw current from external circuit
Solution :
When we measure the emf of a cell by the potentiometer then no current is drawn from the external circuit. Thus, in this condition the actual value of a cell is found. In this way potentiometer is equivalent to an ideal voltmeter of infinite resistance.
NOTE
The emf by the potentiometer is measured from null method in which zero deflection position is found on the wire.