Question
The Ginzburg criterion shows why the onset of this phenomenon appears to be a second-order phase transition, despite it being first-order. For 10 points each:
[10m] Name this phenomenon described by both Ginzburg and Landau's macroscopic mean field theory and BCS theory.
ANSWER: superconductivity [or superconductors or superconducting; accept type I superconductivity] (The Ginzburg criterion shows that the mean-field approximation breaks down within only a small range of the superconducting critical temperature, so the latent heat produced is very small.)
[10e] The mean-field Ising model correctly predicts these materials' second-order phase transition. Nickel, cobalt, and iron exemplify these materials.
ANSWER: ferromagnets [or ferromagnetic materials; prompt on permanent magnets or magnets or magnetic materials; prompt on metals]
[10h] The classification of phase transitions as first or second-order was introduced by this scientist. This scientist names a relativistic paradox and a theorem in quantum mechanics that states that expectation values behave as they do in classical physics.
ANSWER: Paul Ehrenfest ("AIR-in-fest")
<Science - Physics>
Data
Summary
| Tournament | Edition | Exact Match? | Heard | PPB | Easy % | Medium % | Hard % |
|---|---|---|---|---|---|---|---|
| 2025 PACE NSC | 06/07/2025 | Y | 36 | 12.78 | 72% | 42% | 14% |