Voltage Law

There isn't any voltage drop at a single node. Kirchoff's law is used to evaluate the voltage drop between two nodes.

Isolate the node.

OK I admit I am lost, not quite sure of what node refers to in this context. A point of resistance or reactance? In which case it's a simple problem. Or a connection point in which case there is no voltage drop.

in a complicated circuit if the voltage drop across two points have to be found,that is nothing but voltage at one point - voltage at another point,how will u find the voltage at that single point using kvl

By doing the full mesh or nodal analysis.

You also have a significant misunderstanding in measuring a voltage. A voltage measurement is always across two nodes. The voltage at only one node is meaningless. A voltage drop then implies at least three nodes must be present to make a proper measurement.

Fred Quote "The voltage at only one node is meaningless. A voltage drop then implies at least three nodes must be present to make a proper measurement."

No comprende? Why 3?

If there are only two nodes (1,2) then there can only be one and only one voltage V₁,₂. There is no voltage drop. With three or more nodes (1,2,3) there can then be a voltage drop because now the impedance of the components make for more voltages and one can use KVL. V _1,2 + V _2,3 + V _3,1 = 0

You'd probably use Ohm's Law, anyway.

OK. I was using pt1 as one end of the load and pt2 as the other end, therefore 2 pts.

try this!

http://en.wikipedia.org/wiki/Kirchhoff's_circuit_laws

I was thinking of something like this.

There's also a point three between the two light bulbs. If you consider the wiring and fuse resistance then I can quickly add up to almost a dozen points at the start and end of each wire. Depending on how connections are made there can possibly be even another few dozen points when one considers connector pins. I almost forgot about the effect of the source resistance in the battery. This creates a point that one cannot reach or touch but that can be calculated with simple testing.

can u please suggest some book links to become strong in basics of electrical eng. sir

The best book will be the textbook for the class you are taking. There are just to many ways that one can misunderstand what is written. That being said, I used "Electric Circuit Analysis" by David E. Johnson, Johnny R. Johnson, John L. Hilburn & Peter D. Scott.

Thank u:-)