Instructions: In this task you will be given a text passage from a trivia quiz. You should choose the category this question belongs to from these categories: History, Science, Social Science, Fine Arts, Literature. You can only choose one category, so if in doubt, please choose the closest match.
Input: Metals exposed to them induce the creation of Landau levels, allowing the mapping of Fermi surfaces through the De Haas-van Alphen effect. In some elements, such as bismuth, their presence gives rise to forces that attempt to counter or expel them, the most famous example of which is seen in semiconductors via the Meissner effect. They fall off as the inverse of the distance around a current carrying wire, and can be represented by continuous lines that emerge from north-seeking poles and enter south-seeking poles. FTP, what are these regions in which the namesake force is observable
Output:
Science