Physics
Physics
Problem
A junction connects three wires. Current flows toward the junction through wire 1, current flows away from the junction through wire 3, and the current in wire 2 is unknown. Calculate both the magnitude and direction (toward or away from the junction) of required for charge conservation at the junction.Intuitive explanation
This problem tests Kirchhoff's Current Law (KCL), which states that charge cannot accumulate at a junction—all current flowing in must equal all current flowing out. Set up the equation by treating currents flowing toward the junction as positive and currents flowing away as negative (or vice versa, as long as you're consistent), then solve for the unknown. The direction of will reveal itself from the sign of your answer.
Intuitive explanation
This problem tests Kirchhoff's Current Law (KCL), which states that charge cannot accumulate at a junction—all current flowing in must equal all current flowing out. Set up the equation by treating currents flowing toward the junction as positive and currents flowing away as negative (or vice versa, as long as you're consistent), then solve for the unknown. The direction of will reveal itself from the sign of your answer.