Definition: 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: In magnetohydrodynamics it determines whether or not a magnetic field will diffuse away or remain frozen in the plasma and its magnetic version is dependent on the velocity and electrical conductivity of a plasma. It is involved in a solution of the Hagen-Poiseuille equation used to approximate the Darcy friction factor and the drag coefficient must be a universal function of it. This quantity is highly dependent on the characteristic length of the region of fluid flow, and is proportional to the ratio of a fluid's inertia to its kinematic viscosity. When this value is low, it corresponds to a smooth, layered flow. For 10 points, identify this dimensionless quantity related to the turbulence of a fluid.
Output:
Science