Current has not a personality or its own intelligence. Therefore the electrons don’t know where to flow. They flow through the directed path if they can. They are directed by some attracting and repelling forces. See the circuit shown below.
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A battery has two terminals one is positive and the other is negative. The charge is separated as protons are in the positive terminal side and the electrons are in the negative terminal side. Protons are immobile. Therefore electrons come to the protons. If it is connected through a wire having a resistance, the electrons will start to flow from –ve to +ve. But note that electrostatic force is short range force. Moreover, a proton can make only a small electric field around it. I mean that a proton in the +ve terminal can never attract directly an electron in the negative terminal, since there is long path to attract an electron from the –ve terminal. Whatever it is, you know only that the current will flow through the resistance wire. To explain this phenomenon, we should know the material properties of the resistance wire.
A conductor having a particular resistance means that it has some conductance. The conducting material contains a large number of mobile electrons. This makes the conductor conductive. If it is connected to a DC voltage source, (see figure) the electrons in the end of A of the conductor attracted towards the +ve terminal.
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At the same time, some of the +ve charged protons become discharged due to the presence of electrons at A. Thus net potential decreases at +ve terminal. Thus equal amount electrons are liberated at –ve terminal. These electrons are pushed to the end B of the conductor.
When some of electrons at end A leave the conductor wire, there is some void in the conductor. The void is filled by near by electrons and this process continues up to the end B. The pushing of electrons from the end B also helps this process. This continuous process is called as current. The direction of current is taken as +ve to –ve, however the actual current of electrons is from –ve to +ve. This is not matter in mathematical calculation however it is ambiguous if thinking in a logical way.
Resistance
Resistance is the ability of a conductor to prevent current. Mathematically it has greater validity, however physically or logically, use of conductance is more convenient. Conductance increases with increase in the no of mobile electrons present in the conductor at its neutral state. The conductivity increases with increase in the mobile electrons. The conductivity of a conductor can be increased by ejecting electrons from their valance band to conduction band. This can be done by applying heat energy.
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