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 resistivity of the wire increases when it is heated.
B) Arnell, because the resistivity of the wire decreases when it is heated.
C) Jadeen, because the resistivity of a wire is inversely proportional to its area and directly proportional to its length.
D) Jadeen, because the resistivity of a copper wire does not decrease when it is hammered.
E) Both are correct because (a) 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 its resistance due to the physical dimensions affecting the resistance (resistance is directly proportional to length and inversely proportional to cross-sectional area). Arnell's method increases resistance by heating the wire, which increases its resistivity because the atomic lattice vibrates more at higher temperatures, making it harder for electrons to pass through, thus increasing resistance.

Jadeen Says That You Can Increase the Resistance of a Copper