4K. Enough for to make "low temperature superconductors" like regular metals superconducting.
Contrast with liquid nitrogen, which is much cheaper but only goes to 77K.
- Helium | 0, 153, 5
- Chemical element | 0, 733, 46
- Chemistry | 136, 2k, 98
- Natural science | 0, 61k, 2k
- Science | 0, 66k, 2k
- Ciro Santilli's Homepage | 262, 218k, 4k
- Liquid nitrogen | 139
- Superfluid helium-4 | 41