A copper wire of initial length 2.0 m and diameter 1.0 mm is stretched uniformly, without addition or loss of material, until its length becomes 4.0 m. Assume the temperature remains constant and the material remains copper throughout the process.
(a) Calculate the factor by which the wire’s electrical resistance changes as a result of the stretching.
(b) Describe, with reference to relevant physical quantities, why stretching the wire in this manner produces the change in resistance you calculated in part (a).