Question:
Two copper wires have the same mass and, necessarily, the same
volume. The first wire is twice as long as the second. What is the ratio of
their resistances?

Replies:
Resistance is proportional to length and inversely proportional
to cross-sectional area. Another way to work the problem is to imagine two
identical wires of resistance R laid (1) side by side. The total resistance
is R/2 (2) end to end. The total resistance is 2R.

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.