Question

How will the resistivity of a conductor change when its length is tripled by stretching it?

Answer 1

The resistivity will not change because it only depends on nature and temperature

Answer 2

Resistivity is a fixed quantity as it is a property of the conductor. When the length is tripled, the resistance also changes (Reply if you want me to explain the change in resistance). The change in resistance cancels out the change in length. And thus the Resistivity stays unchanged.