What is the phenomenon called when the resistance of certain materials drops to absolute zero when cooled below a characteristic critical temperature?

💡 Solution & Explanation

Superconductivity is a macroscopic quantum phenomenon characterized by exactly zero electrical resistance and the complete expulsion of magnetic fields when certain materials are cooled below a specific critical temperature. Ferromagnetism and thermoelectric effect involve entirely different electromagnetic interactions unrelated to zero-resistance states. Discovered by Heike Kamerlingh Onnes in 1911 in mercury, superconductivity has immense technological applications in particle accelerators and magnetic resonance imaging machines. Materials exhibiting this property must typically be cooled using liquid helium or liquid nitrogen.