Question

a wire of length L and resistance R is stretched so that its length is doubled and its area cross Section halved how will its resistance change resistivity change justify your answer in each case

Answer 1

1.Here, length is doubled and area of cross-section is halved. Thus, a wire of length l and area of cross-section A becomes a wire of length 2l and area of cross-section A/2:
resistance becomes four times

2.Resistivity of a substance does not depend on its length or area of cross-section. It depends on the nature of the material and temperature. Hence there is no change

Answer 2

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Resistivity doesn't depends on the Area of cross section and length , it depends on the nature of the material.

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