Detailed 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.
Q: Landau quantization in two dimensional systems can explain effects due to this entity, which produces a toroidal shape in tokamaks, and is also equal to the curl of the vector potential A. A potential difference is formed when this is applied perpendicularly to the current in the Hall effect, and charge is multiplied by velocity cross this quantity to find the (*) Lorentz force. One can integrate this quantity around a closed loop to find the enclosed current according to Ampere's law, and Gauss's Law states that the net flux of this through a surface is zero. The SI unit of Tesla measures, for ten points, what counterpart to the electric field
A:
Science