SOLUTION

The pure inductive circuit takes power (reactive) from the AC line when applied voltage decreases but current Increases.

In the case of a pure inductive circuit, the current in the circuit lags voltage by 90°. Hence calculation of power is positive when multiple of current and voltage is positive.

• When the applied voltage decreases toward zero levels, the magnetic field collapses. As the magnetic field collapses, the opposition to current flow decreases.
• The decrease in opposition allows the current flow to increase.
• Current flow is at its maximum or peak value when its opposition is at its minimum value.
• The minimum opposition occurs when the applied voltage is also at the minimum value.
• Therefore, when the applied voltage is at its minimum, the current is at its maximum, and when the applied voltage is at its maximum, the current is at its minimum.
• In fact, the current reaches its peak value after the voltage has peaked, which is a purely inductive circuit that occurs 90° after the voltage peaks.
• Therefore, in a purely inductive circuit, the current lags the voltage by 90°. This is possible when the voltage decreases and the current waveform increases.