Question

a wire of length l and a resistance r is streached so that length is double and area of cross section halved. how will (a) resistance change, (b) resistivity change​

Answer 1

Answer:

The resistance will be 4 times i.e. 4r and resistivity will be same.

Explanation:

R∝l

R∝1/A

so l is doubled and A is halved, then R will be 4 times.

Resistivity is constant that  depends on material of wire that does not changed hence resistivity not chnged