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A wire of a certain material is stretched slowly by ten per cent. Its new resistance and specific resistance become respectively:
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- 1.2 times, 1.3 times
- 1.21 times, same
- both remain the same
- 1.1 times, 1.1 times
Correct Option: B
| Resistance of a wire is given by R = ρ | ||
| A |
| If the length is increased by 10% then new length l' = l + | 1 | = | 11 | l |
| 10 | 10 |
In that case, area of cross-section of wire would decrease by 10%
∴ New area of cross-section
Thus the new resistance increases by 1.21 times. The specific resistance (resistivity) remains unchanged as it depends on the nature of the material of the wire.
