Does the length and diameter of a conductor affect its resistance.

• A. No, length and diameter do not affect resistance.
• B. Yes, resistance increases with larger diameter.
• C. Yes, resistance increases if longer, decreases if shorter.
• D. Only diameter affects resistance.

Answer: (C)

Resistance changes with both how long the conductor is and how much cross-sectional area the current has to flow through. A longer wire forces electrons to travel a longer distance, which means more collisions with atoms and more energy lost as heat, so the resistance goes up. Shortening the wire reduces that travel distance, leading to fewer collisions and lower resistance. The diameter (or cross-sectional area) works in the opposite way: a larger diameter gives more area for current to spread out, lowering resistance, while a smaller diameter constrains the flow and raises resistance. So, longer length increases resistance, while shorter length decreases it.