AIPMT PRELIMS 2004 Physics Resistance and Resistivity MCQ Question
The electric resistance of a certain wire of iron is R. If its length and radius are both doubled, then:-
The resistance will be halved and the specific resistance will remain unchanged
The resistance will be halved and the specific resistance will be doubled
The resistance and the specific resistance, will both remain unchanged
The resistance will be doubled and the specific resistance will be halved
Correct Answer
Detailed Explanation
Resistance R is proportional to length and inversely proportional to the cross-sectional area. Doubling both length and radius results in halving the resistance.
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