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Question
Distinguish between a potentiometer and a voltmeter.
Solution 1
| Potentiometer | Voltmeter | |
| 1. | The emf of a cell, potential difference, and internal resistance are all measured with a potentiometer. | A voltmeter can be used to determine a cell's potential difference and terminal voltage. However, it cannot be used to measure the emf of a cell. |
| 2. | It has a high level of accuracy and sensitivity. | Its accuracy and sensitivity are less as compared to a potentiometer. |
| 3. | It is not a portable instrument. | It is a portable instrument. |
| 4. | It does not give a direct reading. | It gives a direct reading. |
Solution 2
| No. | Potentiometer | Voltmeter |
| i. | Its resistance is infinite. | Its resistance is high but finite. |
| ii. | It does not draw any current from the source of known e.m.f. | It draws some current from the source of e.m.f. |
| iii. | The potential difference measured by it is equal to the actual potential difference (p.d.). | The potential difference measured by it is less than the actual potential difference (p.d.). |
| iv. | It has high sensitivity. | It has low sensitivity. |
| v. | It measures e.m.f as well as p.d. | It measures only p.d. |
| vi. | It is used to measure the internal resistance of a cell. | It cannot be used to measure the internal resistance of a cell. |
| vii. | It is more accurate. | It is less accurate. |
| viii. | It does not give a direct reading. | It gives a direct reading. |
| ix. | It is not portable. | It is portable. |
| x. | It is used to measure lower voltage values only. | It is used to measure lower as well as higher voltage values. |
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