Question

Superconducting magnets possess a "cold head" that pumps cryogen to keep the magnet internal temperature at which of the following temperature(s)?

A)320°C
B)-269°C
C)4°C
D)4°K

Answer 1

The cold head in superconducting magnets maintains an internal temperature of 4°K, ensuring that materials like NbTi and Nb3Sn achieve superconductivity. Liquid helium, with a boiling point of 4°K, is commonly used for this purpose, although high-temperature superconductors exist that operate at temperatures much higher than a few kelvin.

Step-by-step explanation:

Superconducting magnets have a cold head that is essential for maintaining the magnet's internal temperature at extremely low levels to achieve superconductivity. The correct answer to the question about the temperature at which the cold head keeps the magnet is D) 4°K. This is because most commercial superconducting materials, such as NbTi and Nb3Sn, require cooling below 23 K (-250 °C), and the boiling temperature of liquid helium used in this process is 4 K. High-temperature superconductors are those that become superconducting at temperatures significantly above a few kelvin, where some have critical temperatures greater than 125 K.