What environmental condition limits the usefulness of materials that appear to lack resistance?

This is a physics problem that I have. It is actually a two part question.



a. What class of materials appear to lack resistance?



b. What environmental condition limits the usefulness of this property?



I beleive that the the answer to question a is conductors. I am not sure about question b.What environmental condition limits the usefulness of materials that appear to lack resistance?a. Materials with no resistance whatsoever are called superconductors.



b. Superconductivity only occurs (so far) at extremely low temperatures, so it's hard to get much use from them.What environmental condition limits the usefulness of materials that appear to lack resistance?a) superconductors

b) currently no materials are able to undergo superconductivity at room temperature. New materials are always being discovered but currently, most superconductors need to be chilled to temperatures of less than 120K. Liquid nitrogen is commonly used to cool superconductors as it stays at about 77K while it is evaporating.