NCERT Class XII Chapter
Current Electricity
Questions With Solutions
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Question : 17
Total: 24
What conclusion can you draw from the following observations on a resistor made of alloy manganin?
| Current A | Voltage V | Current A | Voltage V |
|---|---|---|---|
| 0.2 | 3.94 | 3.0 | 59.2 |
| 0.4 | 7.87 | 4.0 | 78.8 |
| 0.6 | 11.8 | 5.0 | 98.6 |
| 0.8 | 15.7 | 6.0 | 118.5 |
| 1.0 | 19.7 | 7.0 | 138.2 |
| 2.0 | 39.4 | 8.0 | 158.0 |
Solution:
We can find resistance of the alloy manganin for all the readings as follows
here we can conclude that Ohm’s law is valid to a high accuracy and resistance of the alloy is nearly constant at all currents.
| Current A | Voltage V | Resistance Ω |
|---|---|---|
| 0.2 | 3.94 | 19.7 |
| 0.4 | 7.87 | 19.675 |
| 0.6 | 11.8 | 19.667 |
| 0.8 | 15.7 | 19.625 |
| 1.0 | 19.7 | 19.7 |
| 2.0 | 39.4 | 19.7 |
| 3.0 | 59.2 | 19.13 |
| 4.0 | 78.8 | 19.7 |
| 5.0 | 98.6 | 19.72 |
| 6.0 | 118.5 | 19.75 |
| 7.0 | 138.2 | 19.74 |
| 8.0 | 158.0 | 19.75 |
here we can conclude that Ohm’s law is valid to a high accuracy and resistance of the alloy is nearly constant at all currents.
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