A copper wire iis stretched to make it `0.1%` longer. What is the percentage change in its resistance?

Explanation

`R=p 1/A=(p.1)/(V//l)=(p I^2)/V` (V= volume of wire) `therefore R prop I^2` ( p and V= constant)
For small percentage change , % change R=2(% change in l)=2 (0.1%)=0.2%=`1/5 %`
Since `R prop I^2` with increase in the value of `J_1` resistance will also increase