MHT CET2007PhysicsElectrostatics
Potentiometer measures the potential difference more accurately than a voltmeter because
Options
- Ait has a wire of high resistance
- Bit has a wire of low resistance
- Cit does not draw current from external circuit
- Dit draws a heavy current from external circuit
Correct answer
C. it does not draw current from external circuit
Step-by-step solution
When we measure the emf of a cell by the potentiometer then no current flows in the circuit in zero-deflection condition ie, cell is in open 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 in the potentiometer is measured by null method in which zero deflection position is found on the wire.