Question

if a wire of resistivity (p) is stretched to thrice its initial length, what will be its new resistivity?

Answer 1

The resistivity of a substance does not depend on its length.so,here by increasing the length of resistivity it will remain same

Answer 2

Resistivity ρ = resistance of a conductor having a unit length and unit area of cross section.

Resistivity is the property of the material and does not depend on the physical / geometry of the substance/object.  It depends on temperature, potential and nature of material.

Resistance R depends on the physical dimensions of the object.