Question

is kirchoff's law applicable for ac circuits??my sir says yes, but how???

Answer 1

he is talking about kirchoff's voltage law/or mesh law/ or loop law any name can be used. here is a wiki link for explanation http://en.wikipedia.org/wiki/Kirchhoff's_circuit_laws

Answer 2

AC is just a mode of current, there is nothing special about a AC circuit other than the current is different to DC

If Ohms law and other laws of DC circuits still apply to AC, then kirchoff is one which does too. Although it gets more complex, when the circuit gets really complex

Answer 3

I'm sorry @javawarrior but this is a common misconception that people (& even physics teachers) have. Applying kirchoff's laws to an a.c circuit requires you to think that there is a potential difference between the ends of an inductor.
But if you look at it from the point of view of pure physics, this idea is absolutely wrong.
Because an inductor is just a piece of wire. There cannot be a "potential difference" between the ends of a piece of metallic wire, remember!!!
If you are confused, I suggest you read one of Prof. Walter Lewin's most excellent lecture supplements here:
http://ocw.mit.edu/courses/physics/8-02-electricity-and-magnetism-spring-2002/lecture-notes/lecsup41.pdf

Answer 4

And all of you who think there is a "potential difference" between the ends of an inductor should seriously watch this video completely:
http://ocw.mit.edu/courses/physics/8-02-electricity-and-magnetism-spring-2002/video-lectures/lecture-16-electromagnetic-induction/
PLEASE!! FOR THE SAKE OF CORRECT UNDERSTANDING

Answer 5

Kirchhoff's laws apply to AC circuits either:

to intantaneous values of currents and voltages
or to complex values of currents and voltages

but never to:
rms values of currents and voltages.

Answer 6

"Because an inductor is just a piece of wire. There cannot be a "potential difference" between the ends of a piece of metallic wire, remember!!!"

Remember this, the secondary of a high voltage transformer is just a piece of wire, but I assure you if you put one finger on one secondary terminal and a finger from your other hand on the other secondary terminal, the "no potential difference" will convince you otherwise. In fact, it may be your last lesson in life.!