A Level Physics Practice Exam

What defines a superconductor?

1. A material with high resistivity

2. A material that exhibits increased conductivity

3. A material with zero resistance

4. A material that conducts at high temperatures

The correct answer is: A material with zero resistance

A superconductor is defined by its ability to exhibit zero electrical resistance when cooled below a certain critical temperature. This means that when a material transitions into a superconducting state, it can conduct electric current without any energy loss due to resistance. This property is fundamentally different from regular conductive materials, which always exhibit some degree of resistance. Superconductors also exhibit the phenomenon of magnetic flux exclusion, known as the Meissner effect, which occurs alongside the zero-resistance property. This unique behavior is utilized in various applications, including magnetic levitation and powerful electromagnets. The other options do not accurately describe the defining characteristic of superconductors. For instance, a material with high resistivity would not be able to efficiently conduct electricity, while a material that exhibits increased conductivity does not specifically indicate the zero-resistance state that characterizes superconductors. Similarly, a material that conducts at high temperatures does not align with the definition of superconductivity, as most superconductors require very low temperatures to reach their superconducting state.