The length of a certain wire is doubled and at the same time its radius is tripled. What is the change in the resistance of this wire?
A) It stays the same.
B) It is reduced by a factor of 4.5.
C) It is doubled.
D) It is tripled.
E) It is quadrupled.

Question

Quizplus · Accepted Answer

Resistance is inversely proportional to the cross-sectional area and directly proportional to the length. Doubling the length doubles the resistance, while tripling the radius increases the area by a factor of 9, reducing the resistance by a factor of 9. Overall, the resistance is reduced by a factor of 4.5 (2/9).

The Length of a Certain Wire Is Doubled and at the Same