Copper wire #1 has a length L and a radius b.Copper wire #2 has a length 2L and a radius 2b.Which statement about the resistance across the ends of the wires is true?
A)The resistance of wire #1 is twice as high as that of wire #2.
B)The resistance of wire #1 is equal to that of wire #2.
C)The resistance of wire #1 is half that of wire #2.
D)The resistance of wire #1 is four times higher than that of wire #2.

Question

Quizplus · Accepted Answer

The resistance R of a wire is given by R = ρL/A, where ρ is resistivity, L is length, and A is cross-sectional area. For wire #1, R1 = ρL/πb². For wire #2, R2 = ρ(2L)/π(2b)² = ρL/2πb². Thus, R1 = 2R2, meaning wire #1 has twice the resistance of wire #2.

Copper Wire #1 Has a Length L and a Radius