Question

1. Name the particles which are responsible for the flow of current in a metallic wire.
2. Explain the flow of current in a metallic wire on the basis of movement of the particles named by you above in part (a).
3. What is the cause of resistance offered by the metallic wire in the flow of current through it?

Answer 1

1. Particles responsible for the flow of current in a metallic wire are free electrons.
   
   When no potential difference is applied
2. The free electrons within a metal wire begin to move from the negative end to the positive end when a potential difference is applied across its ends. Electrons moving through a wire in this way are called electric current.
3. A metal includes free electrons and fixed positive ions. Positive ions give away their valence electrons and thus attain a positive charge. Electrons are free for movement, but positive ions do not move; thus, when a potential difference is applied across the circuit, and free electrons begin to move, they collide with these fixed ions. The main reason why the metallic wire offers resistance to the flow of current through it is because of this collision.