Change Of Resistance In Wires By Stretching - Practice Questions & MCQ

1. Stretching of wire

If a conducting wire stretches its length increases area of cross-section decreases but volume remains constant

 Suppose for a conducting wire before stretching

 it’s length = , area of cross-section =, radius =, diameter = ,

 and resistance 

After stretching length =, area of cross-section =, radius = , diameter =

and resistance 

So

But Volume is constant So

Now

• If a wire of resistance R and length l  is stretched to length nl, then new resistance of wire is