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- Question
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
Options- A. 3.84∠20.6° V
- B. 12.8∠20.6° V
- C. 0.3∠20.6° V
- D. 13.84∠69.4° V
- Correct Answer
- 3.84∠20.6° V
- 1. The voltages in Problem 5 are measured at a certain frequency. To make the resistor voltage less than the inductor voltage, the frequency is
Options- A. increased
- B. decreased
- C. doubled
- D. not a factor Discuss
- 2. If the frequency is halved and the resistance is doubled, the impedance of a series RL circuit
Options- A. doubles
- B. halves
- C. remains constant
- D. cannot be determined without values Discuss
- 3. 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
Options- A. 5.51 Ω
- B. 55.15 Ω
- C. 90 Ω
- D. 200 Ω Discuss
- 4. Which of the following power factors results in less energy loss in an RL circuit?
Options- A. 1
- B. 0.8
- C. 0.4
- D. 0.2 Discuss
- 5. If a load is purely inductive and the reactive power is 12 VAR, the apparent power is
Options- A. 0 VA
- B. 12 VA
- C. 6 VA
- D. 24 VA Discuss
- 6. Referring to Problem 18, the circuit impedance is
Options- A. 458 ∠?76° Ω
- B. 4.58 ∠?76° Ω
- C. 458∠76° Ω
- D. 4.58∠76° Ω Discuss
- 7. When the frequency of the voltage applied to a series RL circuit is decreased, the impedance
Options- A. decreases
- B. increases
- C. does not change
- D. cannot be determined without values Discuss
- 8. 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
Options- A. 47∠68.6° Ω
- B. 120∠68.6° Ω
- C. 129∠31.4° Ω
- D. 129∠68.6° Ω Discuss
- 9. 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
Options- A. 8.74 mA
- B. 874 mA
- C. 874 µA
- D. 8.74 µA Discuss
- 10. 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
Options- A. 152.6 Ω
- B. 1,526 Ω
- C. 1,200 Ω
- D. 942 Ω Discuss
RL Circuits problems
Search Results
Correct Answer: increased
Correct Answer: cannot be determined without values
Correct Answer: 55.15 Ω
Correct Answer: 0.2
Correct Answer: 12 VA
Correct Answer: 458∠76° Ω
Correct Answer: decreases
Correct Answer: 129∠68.6° Ω
Correct Answer: 8.74 mA
Correct Answer: 1,526 Ω
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