Which factor does not affect resistance in the relation R = ρL/A?

Which factor does not affect resistance in the relation R = ρL/A?

• A. Temperature
• B. Color of insulation
• C. Length
• D. Material

Answer: (B)

The key idea is that resistance depends on the material’s resistivity, the length of the conductor, and its cross-sectional area, as shown by R = ρL/A. Temperature can change resistivity, and metals typically have higher resistivity at higher temperatures, so resistance can increase. Length affects resistance directly: longer conductors have more resistance. Material determines the base resistivity: different materials (like copper vs aluminum) conduct differently even with the same size. The color of the insulation, however, does not enter this equation and does not change ρ, L, or A. It’s just an identification or protection feature and has no effect on the conductor’s resistance.

The key idea is that resistance depends on the material’s resistivity, the length of the conductor, and its cross-sectional area, as shown by R = ρL/A. Temperature can change resistivity, and metals typically have higher resistivity at higher temperatures, so resistance can increase. Length affects resistance directly: longer conductors have more resistance. Material determines the base resistivity: different materials (like copper vs aluminum) conduct differently even with the same size. The color of the insulation, however, does not enter this equation and does not change ρ, L, or A. It’s just an identification or protection feature and has no effect on the conductor’s resistance.