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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