Class 12-science NCERT Solutions Physics Chapter 3 - Current Electricity
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Current Electricity Exercise 127
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Current Electricity Exercise 128
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Current Electricity Exercise 129
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Current Electricity Exercise 130
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(d) The method would not work if the driver cell of potentiometer had an emf of 1.0 V instead of 2.0 V. This is because if the emf of the driver cell of the potentiometer is less than the emf of the cell, then there would be no balance point on wire.
(e) The circuit would not work well for determining an extremelV small emf. As the circuit would be unstable, the balance point would be close to end A. Hence, there would be a large percentage of error
The given circuit can be modified if a series resistance is connected with the wire AB. The potential drop across AB is slightly greater than the emf measured. The percentage error would be small