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प्रश्न
Why is a potentiometer preferred over a voltmeter for measuring emf?
उत्तर १
A voltmeter to Potentiometer should have an infinite resistance so that it draws no current from the circuit. However, a potentiometer cannot be designed to have infinite resistance. At the null point, a potentiometer draws no current from the circuit, providing a more accurate measurement. As a result, it serves as an ideal voltmeter.
उत्तर २
Potentiometer preferred over a voltmeter for measuring emf due to following reasons:
- The potentiometer is more sensitive than a voltmeter.
- A potentiometer can be used to measure a potential difference as well as an emf of a cell. A voltmeter always measures terminal potential difference, and as it draws some current, it cannot be used to measure an emf of a cell.
- Measurement of potential difference or emf is very accurate in the case of a potentiometer. A very small potential difference of the order 10–6 volt can be measured with it. The least count of a potentiometer is much better compared to that of a voltmeter.
संबंधित प्रश्न
A potentiometer wire has resistance of per unit length of 0.1 Ω/m. A cell of e.m.f. 1.5 V balances against a 300 cm length of the wire. Find the current in the potentiometer wire.
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(a) V cm
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State the underlying principle of a potentiometer ?
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The resistance of the potentiometer wire should ideally be ____________.
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where 'i' is the current in the potentiometer
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