Which statement best describes the effect of material on the resistance of a wire with the same dimensions?

• A. Resistance depends only on length, not material.
• B. Material has no effect on resistance.
• C. A material with lower resistivity yields lower resistance.
• D. A higher resistivity yields lower resistance.

Answer: (C)

The key idea is how easily electrons can move through a material, which is captured by resistivity. The resistance of a wire is R = ρL/A. With the wire's length and cross-sectional area fixed, the resistance depends only on the material through ρ. Lower resistivity means electrons flow more freely, so the resistance is smaller. Higher resistivity hinders flow more, giving a larger resistance. So, a material with lower resistivity yields lower resistance for wires with the same dimensions. The other statements ignore or invert this relationship: resistance is not determined only by length, material does have an effect, and higher resistivity does not yield lower resistance.