Which of the following is a characteristic of steel wire in electrical applications?

Steel wire is commonly used in electrical applications because of its balance of strength and conductivity. While steel does not conduct electricity as efficiently as materials like copper, it still possesses moderate conductivity, making it suitable for certain electrical applications where structural integrity is required alongside electrical performance. Steel wire can withstand tension and is often used in overhead lines and support structures, where high electrical performance is not the primary requirement.

High conductivity is typically associated with materials like copper and aluminum, rather than steel, which helps define why the other options are not suitable in this context. Low thermal conductivity is also characteristic of certain materials but is not particularly relevant to steel wire when its electrical applications are considered. Flexibility under heat does not accurately describe steel wire, as steel can become brittle or lose strength under excessive heating. Therefore, the characteristic of moderate conductivity is the most appropriate description of steel wire in electrical applications.