Which term best describes the effectiveness of an insulating material's ability to resist electrical flow?

Dielectric strength is the term that best characterizes the effectiveness of an insulating material to resist electrical flow. It refers to the maximum electric field that a material can withstand without undergoing breakdown, meaning it can effectively insulate and prevent electrical current from passing through under high-voltage conditions. Essentially, a material with high dielectric strength can maintain its insulating properties even when subjected to significant voltage levels, making it ideal for applications where insulation is critical, such as in capacitors or insulation for wires.

In contrast, other terms like conductivity relate to a material's ability to allow the flow of electricity, with higher conductivity indicating less resistance to flow. Impedance encompasses both resistance and reactance in an AC circuit, not strictly isolating the material's insulating properties. Resistance refers to the opposition to current flow within a conductor, not its insulating capability. Therefore, dielectric strength is the most appropriate term when discussing how well an insulating material can prevent electrical flow.