Question

When an AC source is connected to an ideal inductor, show that the average power supplied by the source over a complete cycle is zero.

Answer 1

Hint: Inductor: An inductor is a passive electronic component which is capable of storing electrical energy in the form of magnetic energy. Basically, it uses a conductor that is wound into a coil, and when electricity flows into the coil from left to right this will generate the magnetic fields in the clockwise direction.

Complete step-by-step solution:
The average power supplied by the source over a complete cycle is given by
$ \Rightarrow P = VI\cos \phi $ …(1)
Here,
V=voltage
I=current
$\cos \phi $=power factor
 For pure inductive circuit, the phase difference between current and voltage is $\dfrac{\pi }{2}$
$ \Rightarrow \cos \phi = \cos \dfrac{\pi }{2}$
$\therefore \cos \dfrac{\pi }{2} = 0$
$ \Rightarrow \cos \phi = 0$
Put the value in equation 1
$ \Rightarrow P = VI\cos \phi $
$ \Rightarrow P = V \times I \times 0$
$ \Rightarrow P = 0$
So the average power dissipated is Zero (0).

Note: One of the principal applications of RMS values is with alternating current and voltages. ROOT MEAN SQUARE VALUE. The value of an AC voltage is continually changing from zero up to the positive peak, through zero to the negative peak and back to zero again. 220V is the RMS value of domestic AC electric supply. This can be verified using a multimeter. Multimeter always shows an RMS value of AC voltages.