Video Transcript
The picture below shows the
electrons and atomic nuclei in a section of copper wire. The blue circles represent
electrons and the red circles represent atomic nuclei. There is an electric current in the
wire, and the electrons in it are moving to the right. What is the direction of
conventional current in the wire?
Here, we’ve been given a diagram
that shows electrons and atomic nuclei in a section of copper wire. There is current present in the
wire, and we’ve been told that electrons are flowing to the right. It’s our job to identify the
direction of the conventional current in the wire.
Now, current is the flow of
electrons. But it’s important to remember that
conventional current was defined under the assumption that current is the flow of
positive charge carriers. In reality, only the electrons move
along the wire. And we know electrons are
negatively charged. These are the only true charge
carriers in the wire.
It’s important to note that even
though the atomic nuclei in the copper wire are positively charged, they don’t move
along the wire. So they are not charge
carriers. There are no positive charge
carriers in the wire, but we can still identify the direction that they would flow
if they did exist in the wire.
Let’s recall that electrons flow in
the opposite direction of conventional current. This is because electrons have the
opposite charge of the fictitious positive charge carriers. Here, we know that electrons are
flowing to the right. So the direction of conventional
current must be the opposite, to the left.
Therefore, we know the correct
answer to our question. The direction of the conventional
current in the wire is to the left.
