Monday 10 December 2012

Current Electricity


Current Electricity

The branch of physics deals with the study of motion of electric charges is called
current electricity. In  an charged metallic conductor at rest, some (not all) electrons are continually moving randomly through the conductor because they are very loosely attached to the nuclei. The thermodynamic internal energy of the materials sufficient to liberate the outer electrons from individual atoms,enabling the electrons to travel through the material. But the net flow of charge at any point is zero. Hence, there is zero current. The external energy necessary to drive the free electrons in a definite direction is called electromotive force (emf). The emf is not a force ,but it is the work done in moving a unit charge from one end to the other. The flow of free electrons in a conductor constitutes electric current 

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