Question

Why do the 'free electron' in a metal wire , 'flowing by themselves', not cause any current flow in the wire ?
urgent.................

Answer 1

HELLO FRIENDS ,
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In a metal wire free electron move randomly and trike each other and loss there energy and vice -versa.so they don't have that much energy that they align in particular direction and move and stop striking each other .so they don't conduct electricity.
But when we apply power to them i.e battery they get energy and flow current.
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Best of luck ;)
ROYALJATT

Answer 2

When there is no potential difference across the ends of a wire, there is no net electric field inside the wire across the ends.  The atoms are vibrating. The electrons inside are able to jump to higher orbits and again come back to lower energy levels after releasing energy.
 
    The movement of electrons remains very much local in the neighbourhood of an atom.  The electrons move in random directions and the net effect is that there is no effective movement of charge in one direction.  Like if  N number of electrons cross a cross section from left to right , then there are N number of electrons crossing from right to left.

When a potential is applied, the electric field exerts a force on the electrons in one direction.  All the electrons will move in one direction causing the current.  The net average speed of electrons is called drift velocity which is of the order of  1 mm/sec.