Which will cause the resistance of a conductor to decrease?

Which will cause the resistance of a conductor to decrease?

• A. Decrease the length and increase the cross sectional area.
• B. Increase the length and decrease the cross sectional area.
• C. Decrease the length only.
• D. Increase the cross sectional area only.

Answer: (A)

Resistance follows R = ρL/A, so it grows with longer paths and shrinks when the cross-sectional area gets larger. Shortening the conductor reduces the distance electrons must travel, lowering resistance. Increasing the cross-sectional area provides more pathways for current and lowers resistance by reducing the current density. Doing both at once amplifies the effect, giving a smaller resistance than changing either parameter alone. That’s why decreasing length and increasing cross-sectional area together will cause the resistance to decrease.

Resistance follows R = ρL/A, so it grows with longer paths and shrinks when the cross-sectional area gets larger. Shortening the conductor reduces the distance electrons must travel, lowering resistance. Increasing the cross-sectional area provides more pathways for current and lowers resistance by reducing the current density. Doing both at once amplifies the effect, giving a smaller resistance than changing either parameter alone. That’s why decreasing length and increasing cross-sectional area together will cause the resistance to decrease.