Current in Circuits Flashcards

All 4 cards in this deck

What happens to current at a junction in a circuit?

Current is conserved: the total current into the junction equals the total current out of it.

What are the steps to find a missing current at a junction?

e.g. 5 A flows into a junction and splits into two branches, one carrying 2 A

1. Total current in = total current out: $5 = 2 + I$
2. Subtract the known branch current: $I = 5 - 2$
3. Missing current $= 3\,\mathrm{A}$

What must a circuit contain for there to be a current in it?

A complete (closed) circuit and a source of potential difference, such as a cell.

True or false? Some of the current is used up as it passes through a lamp.

False. Current is conserved; energy is transferred by the lamp, not current used up.