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The length of a given cylindrical wire is increased by `100%`. Due to the consequent decrease in diameter the change in the resistance of the wire will beA. `300%`B. `200%`C. `100%`D. `50%` |
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Answer» Correct Answer - A (a) If suppose initinal length `l_(1) = 100` then `l_(2) = 100 + 100 = 200` `(R_(1))/(R_(2)) = ((l_(1))/(l_(2)))^(2) = ((100)/(200))^(2) implies R_(2) = 4 R_(1)` `(Delta R)/(R ) xx 100 = (R_(2) - R_(2))/(R_(1)) xx (4 R_(1) - R_(1))/(R_(1)) xx 100 = 300%` |
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