Question #2dc3e
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You might be familiar with the fact that positive charges and negative charges attract each other and that a charge creates an electrical environment (called the electric field) around within which another charge experiences a force.
In order to explain the concept of currents, let us take a cylindrical piece of a conducting substance. We put some negative charge on one end and positive charge on the other. What happens is that, the electrons from the negative end flow towards the positive end due to electrostatic attraction. This is what someone can explain from common sense. Soon, the charges on both sides are neutralized.
Now, let us keep on supplying fresh charges on both the sides and we find that a steady flow of electrons from one side to the other is established.
What we are doing in this case is create a steady difference in potential across the two ends of the conductor and as a result, the free electrons are moving from one side to the other.
This is the basic principle of electric currents. If we have a difference in potential between two points, there is a current flow. (One more criteria is that, the circuit needs to be closed.)
Keep in mind that the source doesn't supply electrons, it just creates an electric field (potential difference) and due to it, the electrons within the conductor experience a force and start to drift from one side to the other constituting an electric current.
