Question

what would happen to resistance of wire if it is stretched to double its length justify

Answer 1

if a wire is stretched, so the area of it's cross section will decrease and resistance will increase .

Answer 2

ans:

riginally Answered: A wire is stretched double its length. what happens to its resistivity?

The Resistivity of the wire will not change with the change in length. Resistivity is a property of the wire, it doesn't depend upon it’s length or cross-sectional area.

However, If you are asking about Resistance, it will increase to 4 times it’s initial value.

Resistance,R = ρl/A

Where,

ρ=Resistivity of the wire

l=lenght of wire

A= cross section of the wire

So, now if you increase the length of wire by 2 times it’s cross-sectional area will decrease by 2 times, because the volume of the wire has to remain constant.

Let, the initial and final radius of the wire be r1,&r2 respectively.