Task: Text Categorization
Input (English): 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.
Output (English): Science