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.

[EX Q]: Instead of employing the Debye-Hull-Scherrer powder method, its namesakes relied on an array of atomic planes. Its namesakes built a vacuum apparatus and employed a hot filament, an accelerating electrode, and an arc-mounted Faraday box. A leak in the vacuum led its namesakes to heat the target, resulting in crystallized nickel, which gave startling results. A plot of collector current against beam energy was explained by constructive interference, and the results in general could be derived by combining Bragg's equation with the de Broglie wavelength for electrons. FTP name this experiment named for two physicists, which proved that electrons diffract.
[EX A]: Science

[EX Q]: Materials with this property can exhibit a noise arising from self-organized criticality known as the Barkhausen effect. The Ising model was originally formulated to study this phenomenon, in which regions become separated by Bloch walls and materials exhibiting this property are frequently subject to hysteretic effects. The anti variety of this property disappears above the Neel point, while this property itself disappears above the Curie point, where the material transitions to paramagnetism. FTP, identify this form of magnetism resulting from the spontaneous alignment of domains, which is present in metals such as nickel and iron.
[EX A]: Science

[EX Q]: Shortly after this man's election as president, cotton mill workers took over the Yarur factory. This man came into office as part of the newly formed Popular Unity Party, which increased its share of parliament months before this man was killed inside La Moneda Palace during a military coup. For 10 points, name this socialist president who was elected in 1970 and removed in 1973 by Augusto Pinochet as leader of Chile.
[EX A]:
History