Question

A wire of length L and cross-sectional area A has resistance R.

Answer 1

Answer:

The resistance R stretched of the wire if it is stretched to twice its original length is [Δ(2L) / A ]* 2

Explanation:

Original Resistance R = ΔL / A

Given length is doubled

New length  L' = 2L

New Volume is constant, resistivity and density of material is also assumed to be constant

AL = A'L'

AL = A'(2L)

A' = AL / 2L

A' = A / 2

∴ new Resistance R' = ΔL' / A'

                                 =  Δ(2L) / A/2

                                  = [Δ(2L) / A ]* 2