Question

Apply the junction rule at point a in Figure 21.55.

Final Answer

$I_3 = I_1 + I_2$

### Solution video

# OpenStax College Physics for AP® Courses, Chapter 21, Problem 35 (Problems & Exercises)

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Video Transcript

This is College Physics Answers with Shaun Dychko. The Junction Rule says that all the currents going into a point equals the sum of all the currents leaving that point or that junction. And so this junction here has a current

*I3*going into it. So we have the total of all the currents going in of which there’s only one, so it’s*I3*equals the total of the currents coming out which is*I1*and*I2*. So there’s our Junction Rule written out separately.