Tue May 15, 2012 By: Asmita

The direction of electric current is always shown from +ve terminal to -ve terminal. Why ?

Expert Reply
Tue May 15, 2012
The flow of electric current occurs because we have a high potential of electrons gathered at the positive terminal and a low potential of electrons at the negative terminal. 

The notion of flow of current from +ve to -ve is based on the concept that positive if some thing where you have something excess and negative is something which is in shortage.  This is however not true in case of an electrolytic cell where +ve terminal lacks electrons and the -ve terminal has excess electrons. Actual situation is described below:

Inside a electrolytic or galvanic cell the electrons flow from the Carbon Rod (anode) to the Zinc  Shell (cathode) and by virtue of that there is shortage of electrons on the anode and it gets a positive charge. On the other hand, electrons accumulate on the cathode and it gets the negative charge. When anode and cathode of the cell are connected by a wire through a lamp, the electrons (current) actually flows through the circuit from cathode (-ve terminal) to anode (+ve terminal) in the wire and lamp and from +ve to negative in the electrolite.

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