Video Transcript
The diagram shows an electric
circuit containing a cell and a bulb. Which component in the circuit
provides an electric potential difference?
Here, we are shown a diagram of an
electric circuit with components consisting of a cell, wire, and a bulb. We’re asked which of these
components provide the electric potential difference to the circuit. First, let’s remind ourselves what
we mean by potential difference. Recall that a current is the flow
of electrons around a circuit. Whenever electrons are being made
to move from one point to another, we can say that there’s a potential difference
between these points. Only certain devices can produce an
electric potential difference. One of the most common devices that
produces a potential difference is a cell.
A cell is made up of two terminals,
one positive and one negative. In a cell, electrons are
effectively pushed out of the negative terminal so that they move around the circuit
and move into the positive terminal. This is how a cell provides a
potential difference to a circuit. So we know that a cell can provide
a potential difference to a circuit. Let’s briefly think about the other
options.
Although electrons travel through
wires in a circuit, the wire itself does not produce a potential difference. If there is no cell connected to
the wires, the electrons in the wires will not move. In order for a bulb to light up,
there must be a potential difference across the bulb. However, the bulb itself does not
provide this potential difference. This potential difference must be
provided by another device, like a cell.
So the only device in this circuit
that can provide a potential difference is the cell. This is our answer to the
question.
