Superconductors have-

zero resistivity.

The correct answer is Option (3) → zero resistivity.

Superconductors are materials that exhibit a unique property when cooled below a certain critical temperature. Let us analyze the given options in detail:

Properties of Superconductors

1. Zero Resistivity:

Superconductors have zero electrical resistance when cooled below their critical temperature. This means that they can conduct electricity without any energy loss. This property is fundamental to superconductivity and allows for the phenomenon of persistent currents.

2. Finite Conductivity:

This is incorrect. While regular conductors have finite conductivity, superconductors specifically have zero resistivity.

3. Infinite Resistivity:

This is also incorrect. Infinite resistivity would imply that the material cannot conduct electricity at all, which is the opposite of what superconductors do.

4. Zero Conductance:

This statement is incorrect as well. Conductance is the reciprocal of resistance. If a material has zero resistance, it has infinite conductance, not zero conductance.

Conclusion

The correct statement about superconductors is: zero resistivity.

This means that superconductors allow electric current to flow through them without any resistance, enabling unique applications such as lossless power transmission and powerful electromagnets.