What is the power factor of a purely inductive circuit?

In a purely inductive circuit, the power factor is defined as the cosine of the phase angle between the voltage and the current. For a purely inductive circuit, the current lags behind the voltage by 90 degrees. The cosine of 90 degrees is 0, which means the power factor is 0.

This indicates that while the circuit may have voltage and current flowing through it, there is no real power being used to perform work, as all the power is reactive. Reactive power in inductive circuits is necessary to establish magnetic fields, but it does not contribute to doing any actual work. A power factor of 0 is indicative of a situation where all the current is reactive, emphasizing the nature of purely inductive loads where energy is alternately stored and released by the inductance without any net energy consumption.