Four wires are soldered together at a small junction
PHYSICS · Multi-part · Fermi University Physics · Electricity, Magnetism & Electromagnetism · Electric current and circuits · Electric current and circuits
Electricity, Magnetism and Electromagnetism, Ch Current, current density, conductivity and Ohm's law
Problem
Four wires are soldered together at a small junction. All currents are steady, so no charge piles up anywhere at the junction. Measurements give: 2.5A flowing into the junction along wire 1, 1.8A flowing into the junction along wire 2, and 3.1A flowing out of the junction along wire 3.
((a)) Using a closed surface that encloses the junction and cuts each of the four wires once, state the value of the outward flux ∮SJ⋅dA for this steady state.
((b)) Find the magnitude of the current in wire 4 and say whether it flows into or out of the junction.