Which factor is not among the four factors affecting resistance?

• A. length
• B. ambient humidity
• C. cross sectional area
• D. temperature

Answer: (B)

Resistance of a conductor is determined by the material’s resistivity, its length, and its cross-sectional area, with temperature also playing a role. The formula R = ρL/A shows how each factor affects resistance: longer lengths increase resistance, larger cross-sectional areas decrease it, and changing temperature alters the material’s resistivity (metallic resistivity typically rises with temperature). Ambient humidity does not change the intrinsic resistance of the conductor itself under normal conditions; it may affect insulation or contacts, but not the bulk resistance. That’s why humidity isn’t counted among the four factors that govern resistance.