Power Factor
In AC circuits, the power factor is the ratio of the real power that is used to do work and the apparent power that is supplied to the circuit.
The power factor can get values in the range from 0 to 1.
When all the power is reactive power with no real power (usually inductive load) - the power factor is 0.
\[E=IZ= \frac{P}{Icos\theta }=\sqrt{\frac{PZ}{cos\theta }} \]
let value of 
= x degree.
