Which statement best describes Kirchhoff's Current Law?

• A. The algebraic sum of currents at a node is zero.
• B. Current always flows equally in all branches of a node.
• C. Voltage, not current, is conserved at a node.
• D. Only DC currents are subject to Kirchhoff's laws.

Answer: (A)

Kirchhoff's Current Law is about current balance at a junction: the algebraic sum of currents at a node is zero. This reflects conservation of charge: what goes into a junction must come out of it. When you analyze a node, assign a direction to each branch current and treat currents entering the node as positive and those leaving as negative (or the opposite). The signed currents at the node add up to zero, meaning the current flowing into the node equals the current flowing out.

For example, if two branches push 3 A and 2 A into the node, and another branch takes 5 A away, the signed sum is 3 + 2 − 5 = 0, which satisfies the law.

This means currents don’t have to be equal in every branch; they just have to balance at the node. It’s not about voltage conservation at a node, and Kirchhoff’s laws apply to both DC and AC situations in lumped circuits, not just steady DC.