The ____ of a conductor is measured in mm2, circular mils, or in2.

The area of a conductor is indeed measured in square millimeters (mm²), circular mils, or square inches (in²). This measurement is essential as it relates to the conductor's capacity to carry electrical current safely and efficiently. The larger the cross-sectional area, the more current it can handle without overheating, thus affecting the overall performance of an electrical system.

Measurements of length, weight, or impedance refer to other properties of the conductor. Length pertains to how long the conductor is, which affects resistance but not the ability to carry current directly. Weight relates to the material used and density, not how much current can safely pass through. Impedance is a broader term involving both resistance and reactance in AC circuits, which again is not directly related to the cross-sectional area measurement of a conductor. Therefore, the correct focus on area underscores its critical role in electrical design and safety.