How does contact area affect skin resistance?

How does contact area affect skin resistance?

• A. Larger contact area increases resistance
• B. A larger contact area reduces overall resistance, allowing more current to flow.
• C. Contact area has no effect on resistance
• D. A larger contact area increases the resistance only if voltage is high

Answer: (B)

When the contact area between the skin and the conductor increases, the path for current has a larger cross-sectional area. Resistance depends inversely on that area (R = ρL/A). So, larger contact area lowers the skin’s resistance. With a fixed voltage, Ohm’s law (I = V/R) tells us that lowering resistance allows more current to flow. In practical terms, a bigger, wet, or well‑seated contact patch can carry more current than a small or dry patch, which affects safety because higher current can be more dangerous. The key idea is that area and resistance move in opposite directions, and voltage alone doesn’t change that fundamental relationship.

When the contact area between the skin and the conductor increases, the path for current has a larger cross-sectional area. Resistance depends inversely on that area (R = ρL/A). So, larger contact area lowers the skin’s resistance. With a fixed voltage, Ohm’s law (I = V/R) tells us that lowering resistance allows more current to flow. In practical terms, a bigger, wet, or well‑seated contact patch can carry more current than a small or dry patch, which affects safety because higher current can be more dangerous. The key idea is that area and resistance move in opposite directions, and voltage alone doesn’t change that fundamental relationship.