Jadeen says that you can increase the resistance of a copper wire by hammering the wire to make it narrower and longer. Arnell says that you can increase its resistance by heating the wire. Which one, if either, is correct, and why?
A) Arnell, because the conductivity of the wire increases when it is heated.
B) Arnell, because the conductivity of the wire decreases when it is heated.
C) Jadeen, because the conductivity of a wire is directly proportional to its area and inversely proportional to its length.
D) Jadeen, because the conductivity of a copper wire does not increase when it is hammered.
E) Both are correct because (b) and (d) are both correct.

Question

Quizplus · Accepted Answer

Both Jadeen and Arnell are correct. Jadeen's method increases resistance by making the wire longer and narrower, which increases resistance due to a longer path for electrons and a smaller cross-sectional area for current flow. Arnell's method increases resistance by heating the wire, which increases the atomic vibrations within the copper, making it harder for electrons to pass through, thus decreasing its conductivity.

Jadeen Says That You Can Increase the Resistance of a Copper