alleryStart learning →POWER FACTOR is defined as
A$\cos\phi$ (V-I phase angle)
B$\sin\phi$
C$\tan\phi$
Dthe ratio of peak voltage to peak current
Answer & Solution
Correct answer: A. $\cos\phi$ (V-I phase angle)
1. POWER FACTOR (PF): $\text{PF} = \cos\phi$.
2. $\phi$ = phase angle between voltage and current waveforms (positive for inductive load, negative for capacitive).
3. APPARENT POWER: $S = V_{RMS} I_{RMS}$ (VA).
4. REAL POWER (actual energy delivered to load): $P = V_{RMS} I_{RMS} \cos\phi = S \cos\phi$ (watts).
5. Power factor close to 1 = efficient. Close to 0 = inefficient (lots of reactive current, less useful work).
6. Other options give related but different quantities.
_Source: Tony Kuphaldt, "Lessons in Electric Circuits — AC", Vol II, Ch 11 (Power factor)._
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