This document contains 5 practice problems related to modeling electrical system elements: 1) Finding the current sheet Js for a current sheet of width 4 m containing 10 A of total current directed from the origin to (1, 3, 0) m. 2) Expressing the current sheet Js for a thin cylindrical sheet of radius 2 cm with current I entering at the top. 3) Finding the total outward current from a 1-meter cube if the current density J is given. 4) Finding the capacitance of a cylindrical capacitor where each dielectric occupies half the volume. 5) Finding the voltage across each dielectric in the capacitor when the applied voltage is 200V.