What is kirchoffs loop rule? Please give explanation.

Around any circuit loop, apply energy conservation in form of

V=  lambda lnRn 

Voltage or electric potential difference is the potential energy per unit charge. So, any description of electric potential or voltage is closely connected with energy.

Consider a simple circuit:

Think of walking this circuit while carrying a charge q. Start at a and ‘walk’ through the battery to b. Potential energy of charge has increased by amount qV. As you walk on to c, nothing happens. As you walk through resistor – from c to d – resistor heats up. You give up potential energy of the charge to the resistor. As you walk back from d to a, nothing happens. 

 

Electric potential V which is ‘gained’ in going through the battery is ‘lost’ in potential difference across resistor IR.

That is all that Kirchoff’s Loop Rule says. As you ‘walk’ around any complete loop in circuit – coming back to where you started – potential energy you gain must equal potential energy you lose or sum of electric potential differences must be zero or sum of positive electric potential differences must equal sum of negative electric potential differences or the sum of all the potential differences due to batteries must equal sum of all potential differences across resistors. That is,

V= lambda lnRn 

In a more complicated circuit, that V should really be the sum of V’s or

lambda V = lambda lnRn