Given the task definition and input, reply with output. 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.

One analogue to this rule is named for Hopkinson and has constant of proportionality the reluctance; this rule and Hopkinsons law may be combined for a circulating magnetic field in a plasma to analyze a namesake form of heating. A generalization of this equation states that the current density equals the sum over n from 1 to infinity of the nth conductivity tensor acting on the nth direct product of the electric field; truncating to first order gives the microscopic form of this law, j equals sigma E, which may be averaged to give the more familiar lumped circuit form. For 10 points, name this physical law that says that the voltage drop is the current times the resistance, or V equals I R; a law named for a German high school teacher.

Science