What determines the DC resistance of a conductor?

The correct option highlights three key factors that influence the DC resistance of a conductor: length, thickness, and temperature.

• Length: The resistance of a conductor is directly proportional to its length. This is because a longer conductor offers more material for the electrons to pass through, thereby increasing the likelihood of collisions with the atoms in the material, which contributes to resistance.

• Thickness: Resistance is inversely proportional to the cross-sectional area (or thickness) of the conductor. A thicker conductor has a larger area for the electrons to flow through, which reduces the resistance. Essentially, more pathways for the electrons lead to lower resistance.

• Temperature: The resistance of a conductor is also affected by temperature. As temperature increases, the atoms in the conductor vibrate more intensely, which can impede the flow of electrons and hence increase resistance. Conversely, at lower temperatures, resistance typically decreases.

These three factors together capture how the physical characteristics of a conductor determine its ability to resist the flow of electric current. The other options include factors that do not directly impact DC resistance in the way that length, thickness, and temperature do, thereby confirming why this choice is the most accurate.