PHYSICS -alternating current?

Question

I feel confusion in justifying one of the property of PARALLEL RESONANCE CIRCUIT R-L-C that is the branch current through inductance and branch current through capacitance may be much larger than source current at resonance.

My question is that how here kirchhoffs second rule of voltage is obeyed"

Answer 1

Kirchhoff’s Second Rule:

“The directed sum of the electrical potential differences around any closed circuit must be zero.”

Kirchhoff’s law does not directly apply to AC RLC circuits.  Inductors and capacitors cause current and voltage to be out of phase from 0 to 90 degrees, making Kirchhoff’s law inaccurate.

For Kirchhoff’s Law to be accurately applied to an AC RLC circuit, the circuit and applied voltage must be resonant, or appear purely resistive to the source.

For more information on how to accurately calculate the impedance (X^L, X^C, and R) please see the following link:

http://www.tpub.com/neets/book2/4e.htm

Answer 2

Great question. The simplest way to explain it is that -10 plus 8 is merely 2.

The two branch currents may be very large in magnitude, but if one is pushing when the other is pulling, and vice-versa, their sum can be very small indeed.

The source current is the sum of the two branch currents. So long as the two branch currents largely pull in different directions (the capacitor charges while the inductor breaks down its field, the capacitor discharges as the inductor builds its field) you can have large currents between these branches without a large source current.

A more accurate way to think about it is a vector sum. Imagine a large vector going straight up and an equally large vector going mostly down. The sum of those two will be a small mostly-horizontal vector.