Video Transcript
The diagram shows a circuit
consisting of three cells and a resistor. Complete the following
sentence. The three cells are connected in
blank. (A) parallel, (B) series.
The problem asks us if the three
cells in the circuit diagram are connected in parallel or series. The circuit also includes a
resistor on a separate branch of the circuit. Let’s begin by understanding what
it means for cells to be connected in series or in parallel.
It is said that two or more cells
are connected in series when the cells are connected directly to each other along
the same circuit path. There is only a single path
connecting the cells, with the terminal of one cell connected to the opposite
terminal of the adjacent cell. Normally, the positive terminal of
one cell is directly connected to the negative terminal of the next cell. But when two or more cells are
connected so that there is more than one path connecting the terminals of a cell to
the opposite terminal of the same cell, we say that these cells are connected in
parallel, meaning there are multiple routes by which the terminals of the cells are
connected.
We call each circuit path
containing an element, like a cell or a resistor, a branch. Looking at the visuals, we can see
that cell A is on a separate branch from cell B. Paths one and two connect the
terminals of cell A, and paths three and four connect the terminals of cell B. So now we know these cells are
connected in parallel. If we look back at the diagram
given in the question, we can see that three cells and a resistor have been
connected on four separate branches of the circuit. And they’ve asked us to decide if
the cells are connected in parallel or series. Let’s analyze the different paths
between the cell terminals.
They only ask us only about the
three cells, so we will not look at the resistor, but we can see that the resistor
sits on its own. We can see that the terminals of
cell A are connected along path one, also path two, and path three. For cell B, the terminals are
connected along path four, five, and six. And finally, for cell C, the
terminals are connected along path seven, eight, and nine. So to answer the question, the cell
terminals are connected by multiple paths, the cells are on separated branches, and
so the cells are in parallel. We can complete the sentence with
option (A) parallel.
