Video Transcript
Complete the following
sentence. A battery is a set of blank. (A) resistors, (B) cells, (C)
bulbs.
To complete the sentence, let’s go
through the options and remind ourselves what each one of them is.
Option (A), a resistor is an
electrical component that reduces the current in a circuit. It is not a source of power. Option (B), a cell is a power
source that provides electrical energy to a circuit. This allows a current to flow from
the positive terminal of the cell to the negative terminal of the cell through the
circuit which connects them. Option (C), a bulb is an electrical
component that emits light when current flows through. A bulb is not a power source. It merely transfers the energy
provided by the cell to light.
So, to answer the question, we need
to ask ourselves what a battery is, and then we’ll know whether to choose answer
(A), (B), or (C).
A battery is a power source used in
electrical devices. At home, our television remote
controls, our laptops, and our mobile phones all use batteries of some kind. But what actually is a battery? Well, since a battery is a power
source, it would make sense for a battery to consist of a set of cells, because
cells are also a power source. This is the definition of a
battery: a set of cells connected together in series.
In fact, the circuit symbol for a
battery actually shows two cells connected in series. The connection between cells is
represented by a dashed line. Although only two cells are shown
in the circuit symbol, a battery can consist of more than two cells.
So we know that the answer must be
option (B). A battery is a set of cells, as a
cell is the only component listed in the options that is a source of power. And we can see from the circuit
symbol for a battery that a battery is made up of multiple cells.
