Why does a thin wire have higher resistance than a thick wire?

Why does a thin wire have higher resistance than a thick wire?

• A. Because the thin wire has more electrons to carry the current
• B. Because the cross-sectional area is larger
• C. Because a thin wire has fewer electrons to carry the current flow
• D. Because it uses a different material

Answer: (C)

The main idea is that resistance depends on how much cross-sectional area is available for current to flow. For the same material and length, a wire with smaller cross-sectional area has higher resistance because there are fewer parallel paths for electrons to travel. This means the same voltage pushes the electrons through a narrower channel, increasing collisions (and impedance) per unit current. Saying that a thin wire has fewer electrons to carry the current captures this idea: the narrower cross-section provides fewer carriers in the path, so the overall ability to conduct is reduced, making resistance larger. In contrast, a larger cross-sectional area would provide more paths and lower resistance; using a different material would change resistance through a different resistivity, not just wire thickness.

The main idea is that resistance depends on how much cross-sectional area is available for current to flow. For the same material and length, a wire with smaller cross-sectional area has higher resistance because there are fewer parallel paths for electrons to travel. This means the same voltage pushes the electrons through a narrower channel, increasing collisions (and impedance) per unit current.

Saying that a thin wire has fewer electrons to carry the current captures this idea: the narrower cross-section provides fewer carriers in the path, so the overall ability to conduct is reduced, making resistance larger. In contrast, a larger cross-sectional area would provide more paths and lower resistance; using a different material would change resistance through a different resistivity, not just wire thickness.