Question

A wire of resistivity R is pulled to double its length and area of cross section of a conductor​

Answer 1

Answer:

R=ρL/A

When L becomes 2L, A becomes A/2

New R=ρ 2L/A/2

           =4 ρL/A

           =4 R

New resistance becomes 4 times the original one.

But, resistivity remains the same as it is the property of the substance and does not change with length or area.