Question

A wire of resistivity p is stretched to double its length. Find its new resistance and resitivity

Answer 1

Answer:

We have

Resistance= Resistivity x length/area

When the wire is stretched to double the length , the area of cross section gets reduced to half.

So

New Resistance = Resistivity x 2length/area/2

I.e,

New resistance = (Resistivity x area/length)x4

i.e, New resistance = Resistance x 4

So when the wire is stretched, the resistance multiplies by four times.

Hope you understood. Keep exploring.

Answer 2

Answer:

new resistance is 4r

Explanation: