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Question
Choose the correct alternative:
The resistivity of the alloy manganin is nearly independent of/increases rapidly with increase of temperature.
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Solution
The resistivity of the alloy, manganin, is nearly independent of increase of temperature.
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Two wires of equal length, one of aluminium and the other of copper have the same resistance. Which of the two wires is lighter? Hence explain why aluminium wires are preferred for overhead power cables.
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| 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 |
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