When the material is cooled down under its critical temperature, which of the superconductor attains accidentally zero?

The correct answer is Resistance.

Key Points

• When a material is cooled below its critical temperature, it undergoes a phase transition and can become a superconductor, exhibiting zero electrical resistance.
• In a superconducting state, the material allows for the flow of electric current without any energy loss due to resistance.
• The property of zero electrical resistance is not accidental but rather a defining characteristic of superconductors.
• Once a material reaches its critical temperature, it transitions into a superconducting state, and its electrical resistance drops abruptly to zero.

Additional Information

• Different materials have different critical temperatures. In conventional superconductors, such as elemental metals like mercury or lead, the critical temperatures are generally very low, typically below a few Kelvin (Kelvin is the unit of temperature used in scientific measurements). For example, mercury has a critical temperature of around 4.2 Kelvin.
• In recent decades, high-temperature superconductors (HTS) have been discovered, which have critical temperatures above the boiling point of liquid nitrogen (77 Kelvin or -196 degrees Celsius).
• HTS materials, typically copper oxides or iron-based compounds, can exhibit superconductivity at relatively higher temperatures.