What is the (K) constant for copper?

The constant (K) for copper refers to its electrical conductivity or specific heat value, which is crucial in various electrical calculations. The value of 12.9 pertains to the conductivity of copper when expressed in units such as mhos per centimeter (or similar).

Copper is well known for its excellent electrical conductivity, which is a primary reason it is widely used in electrical wiring and components. The K constant provides a baseline for comparing the conductive properties of different materials, and in this case, 12.9 is recognized as the typical value associated with copper's conductivity, making it the correct answer.

In contrast, other values listed do not accurately represent copper’s conductivity. Each of those values corresponds to different materials or could be mistakenly interpreted regarding copper's conductive properties. Understanding these constants is essential for applications in electrical engineering, ensuring proper material selection based on their conductive efficiencies.