why do we prefer a potentiometer to measure the emf of cell rather than a voltmeter
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A voltmeter determine potential difference as like potentiometer but the voltmeter draws some current from the circuit or u can say need some current to work..hence it will take current from the measuring circuit or points..hence it will not give accurate p.d.
suppose there is a current of 5 ampere and we have to determine the potential difference between the two point in the circuit for that first we use with voltmeter ... it will use current of 0.1 ampere to work then 5-0.1=4.9 A now the voltmeter will show the potential difference of (4.9A × R )V ... but the potentiometer did not need current to work and it will give accurate reading of (5A × R) V ...*R is here for resistance.
V = IR
hope it will help u
suppose there is a current of 5 ampere and we have to determine the potential difference between the two point in the circuit for that first we use with voltmeter ... it will use current of 0.1 ampere to work then 5-0.1=4.9 A now the voltmeter will show the potential difference of (4.9A × R )V ... but the potentiometer did not need current to work and it will give accurate reading of (5A × R) V ...*R is here for resistance.
V = IR
hope it will help u
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