Practice Test: Question Set - 02

1. A 470 Ω resistor and a 200 mH coil are in parallel. Both components are across a 1.5 kHz ac source. The total admittance of the circuit, in polar form, is
(A) 12.60 ∠-76° mS
(B) 12.18 ∠76° mS
(C) 218 ∠-76° mS
(D) 12.18 ∠-76° mS

2. In a series RL circuit, 12 V rms is measured across the resistor, and 14 V rms is measured across the inductor. The peak value of the source voltage is
(A) 18.4 V
(B) 26.0 V
(C) 2 V
(D) 20 V

3. The power factor indicates how much of the apparent power is reactive power.
(A) True
(B) False

4. A 1.5 kΩ resistor and a coil with a 2.2 kΩ inductive reactance are in series across an 18 V ac source. The power factor is
(A) 564
(B) 0.564
(C) 6.76
(D) 55.7

5. Total current in an RL circuit always lags the source voltage.
(A) True
(B) False

6. When the frequency of the voltage applied to a series RL circuit is decreased, the impedance
(A) Decreases
(B) Increases
(C) Does not change
(D) Cannot be determined without values

7. The impedance of an RL circuit varies inversely with frequency.
(A) True
(B) False

8. When the frequency of the voltage applied to a series RL circuit is increased, the phase angle
(A) Decreases
(B) Increases
(C) Does not change
(D) Cannot be determined without values

9. In an RL circuit, the impedance is determined by both the resistance and the inductive reactance combined.
(A) True
(B) False

10. To increase the current in a series RL circuit, the frequency
(A) Should be increased
(B) Should be decreased
(C) Should be constant
(D) Cannot be determined without values

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