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The potentiometer is best for measuring voltage, as :
A
It has a sensitive galvanometer
B
It has wire of high resistance
C
It measures p.d. like in closed circuit
D
It measures p.d. like in open circuit
Detailed Solution
A potentiometer measures voltage by a null (balance) method. At the balance point, no current flows through the galvanometer, i.e. no current is drawn from the cell being measured.
So it measures the potential difference as in an open circuit, i.e. the true emf of a cell, without the drop due to internal resistance.
A voltmeter draws some current, so it measures a slightly lower terminal voltage.
So the potentiometer is best because it measures p.d. as in an open circuit.
So it measures the potential difference as in an open circuit, i.e. the true emf of a cell, without the drop due to internal resistance.
A voltmeter draws some current, so it measures a slightly lower terminal voltage.
So the potentiometer is best because it measures p.d. as in an open circuit.