MCQ
In an $ac$ circuit, the power factor
- AIs zero when the circuit contains an ideal resistance only
- BIs unity when the circuit contains an ideal resistance only
- CIs zero when the circuit contains an ideal inductance only
- ✓Both $(b)$ and $(c)$
✓
Answer
Correct option: D.
Both $(b)$ and $(c)$
d
Power factor, $\cos \phi=\frac{R}{Z}$
Power factor, $\cos \phi=\frac{R}{Z}$
When circuit contains only resistance, then
$Z = R$
$\therefore \cos \phi=1$
When circuit contains only inductance, then
$R =0$
$\therefore \cos \phi=0$
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