### Video Transcript

Which of the following diagrams
shows three cells connected in series?

Recall that in series means that
the cells are connected one after another. So if we draw a path through a
circuit with three cells connected in series, all three cells will be along that one
path. Now, these diagrams don’t show
complete circuits, only parts of circuits. But that’s okay. The idea is the same. We’re going to draw a path from one
end of the diagram to the other. In the diagram on the right, there
are three possible paths going from left to right across the diagram. One path goes up, across, back
down, and out. One path goes straight across the
middle of the diagram. And the last path goes down,
across, back up, and out.

We can see that there is exactly
one cell on each of these three possible paths. Since each path only has one cell,
we know that this diagram doesn’t show three cells in series. Because if there were three cells
in series, all three cells would be on the same path. In the diagram on the left, there’s
only one path, and that path passes through all three cells. And three cells on one path is
exactly what we would expect for three cells connected in series. So the diagram with three cells
connected in series is the diagram on the left. Several cells connected in series
are sometimes called a battery.