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What is the average true power in a purely inductive AC circuit?
Zero
Why does a pure inductor not dissipate power as heat?
Because an ideal inductor stores energy in its magnetic field and returns it to the source
In an inductive circuit, does current lead or lag voltage?
Lag
What unit is used to measure reactive power?
VAR (Volt-Amps Reactive)
What is the formula for calculating reactive power using current and reactance?
Q = I² × X (or Q = V² / X
In a capacitive circuit, current leads or lags voltage?
Lead
What is the formula for capacitive reactance (XC)?
XC = 1 / (2πfC)
Define ‘apparent power’ and state its unit.
Apparent power is the vector sum of true and reactive power, measured in VA (Volt-Amps).
What does a power factor of 1 indicate about a circuit?
That all the power is being used effectively — no reactive component
How is instantaneous power calculated in AC circuits?
p(t) = v(t) × i(t)
In resistive circuits, power is always:
•
Positive
Which type of component alternately stores and returns energy in the form of a magnetic field?
Inductor
How does the frequency affect inductive reactance?
It increases — XL is proportional to frequency.
What type of power is associated with energy returned to the source?
Reactive Power
Which formula correctly represents true power using RMS values?
P = VRMS × IRMS
Explain why the power waveform in AC circuits has twice the frequency of voltage/current.
Because both current and voltage are sinusoidal and their product results in a sine-squared waveform.
