What is the primary characteristic of a superconductor?

• A. High resistance
• B. No resistance
• C. Variable resistance
• D. Low conductivity

Answer: (B)

A superconductor is defined by its ability to exhibit zero electrical resistance when cooled below a certain critical temperature. This phenomenon means that when a material becomes superconductive, it allows electric current to flow through it without any energy loss due to resistance. This characteristic is foundational to the properties of superconductors and is what enables their unique applications, such as in magnetic levitation and efficient power transmission.

While high resistance, variable resistance, and low conductivity describe other materials’ behaviors under different conditions, they do not capture the essence of superconductivity. Instead, the hallmark of superconductors is their complete lack of resistance in their superconducting state, allowing them to maintain current indefinitely without power loss.