RL Circuits MCQ Test - ObjectiveBooks

# Practice Test: Question Set - 03

1. A 140 Ω resistor is in parallel with an inductor having 60 Ω inductive reactance. Both components are across a 12 V ac source. The magnitude of the total impedance is
(A) 5.51 Ω
(B) 55.15 Ω
(C) 90 Ω
(D) 200 Ω

2. A 12 kΩ resistor is in series with a 90 mH coil across an 8 kHz ac source. Current flow in the circuit, expressed in polar form, is I = 0.3 ∠0° mA. The source voltage, expressed in polar form, is
(A) 3.84 ∠20.6° V
(B) 12.8 20.6° V
(C) 0.3 20.6° V
(D) 13.84 69.4° V

3. The resistor voltage in an RL circuit is always out of phase with the current.
(A) True
(B) False

4. In a lag network, the output voltage lags the input voltage in phase.
(A) True
(B) False

5. A 1.2 kΩ resistor is in series with a 15 mH coil across a 10 kHz ac source. The magnitude of the total impedance is
(A) 152.6 Ω
(B) 1,526 Ω
(C) 1,200 Ω
(D) 942 Ω

6. The phase angle (θ) of a series RL circuit varies directly with frequency.
(A) True
(B) False

7. A 3.3 kΩ resistor and a 120 mH coil are in parallel. Both components are across a 2 kHz, 12 V ac source. The total current in the circuit is
(A) 8.74 mA
(B) 874 mA
(C) 874 μA
(D) 8.74 μA

8. A filter passes certain frequencies and rejects others.
(A) True
(B) False

9. A 47 Ω resistor is in series with an inductive reactance of 120 Ω across an ac source. The impedance, expressed in polar form, is
(A) 47 ∠68.6° Ω
(B) 120 ∠68.6° Ω
(C) 129 ∠31.4° Ω
(D) 129 ∠68.6° Ω

10. When the frequency is decreased, the impedance of a parallel RL circuit Increases
(A) True
(B) False

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