Here's a breakdown:

* Superconductivity: This is a phenomenon where the electrical resistance of a material drops to zero below a critical temperature.

* Critical Temperature (Tc): This is the temperature below which a material becomes superconducting.

* Infinite Conductivity: While not truly infinite in practice, the resistance becomes so incredibly low that it's practically immeasurable.

Key Points about Superconductors:

* Not all materials are superconductors: Only certain materials exhibit this property.

* Low temperature requirement: Superconductivity usually occurs at extremely low temperatures, often close to absolute zero (-273.15 °C or 0 Kelvin).

* Types of Superconductors:

* Conventional superconductors: These follow the BCS theory, which explains superconductivity as the pairing of electrons due to interactions with vibrations in the crystal lattice.

* Unconventional superconductors: These don't follow the BCS theory and exhibit more complex mechanisms for superconductivity.

Examples of Superconductors:

* Elemental Superconductors: Mercury, Lead, Niobium

* Alloy Superconductors: Niobium-titanium (NbTi), Niobium-tin (Nb3Sn)

* High-Temperature Superconductors: These operate at higher temperatures (still very low, but above the boiling point of liquid nitrogen).

Applications of Superconductors:

* Magnetic Resonance Imaging (MRI)

* High-speed trains (Maglev)

* Power transmission lines

* Quantum computing

Note: The term "infinite conductivity" is a simplification. While resistance becomes vanishingly small, it doesn't truly become zero. There are always some minor losses, especially in real-world applications.