Inductors problems
- 1. The output phase for a transformer is:
Options- A. in phase with the input
- B. out of phase with the input
- C. dependent on the direction of the primary and secondary windings
- D. dependent on the frequency of the primary source Discuss
Correct Answer: dependent on the direction of the primary and secondary windings
- 2. A practical inductor
Options- A. has inductance
- B. has winding resistance
- C. has winding capacitance
- D. all of the above Discuss
Correct Answer: all of the above
- 3. Which transformer turns ratio is needed to match two 16-ohm parallel devices to an output of 22.2 ohms?
Options- A. 1.38:1
- B. 1.67:1
- C. 0.72:1
- D. 0.60:1 Discuss
Correct Answer: 0.60:1
- 4. When current in an inductor starts to change, it cannot react instantly due to:
Options- A. fixed coil resistance
- B. eddy current generation
- C. applied emf of the circuit
- D. the counter emf of the coil Discuss
Correct Answer: the counter emf of the coil
- 5. What is the phase angle of a 24 Vac parallel RL circuit when R = 45 ohms and XL = 1100 ohms?
Options- A. 0.001 degrees
- B. 2.300 degrees
- C. 87.600 degrees
- D. 89.900 degrees Discuss
Correct Answer: 2.300 degrees
- 6. On a schematic, dashed lines between two vertical coils usually mean the transformer has:
Options- A. an air core
- B. an iron core
- C. a nonmetallic core
- D. a ferrite core Discuss
Correct Answer: a ferrite core
- 7. The polarity of induced voltage while a field is collapsing is:
Options- A. independent of the force creating it
- B. opposite to the force creating it
- C. identical to the force creating the field
- D. present only if the force is stationary Discuss
Correct Answer: opposite to the force creating it
- 8. What is the number of turns required in the secondary winding for a transformer when 120 volts is applied to a 2400-turn primary to produce 7.5 Vac at the secondary?
Options- A. 75 turns
- B. 150 turns
- C. 900 turns
- D. 1920 turns Discuss
Correct Answer: 150 turns
- 9. A loaded transformer will achieve mutual induction when:
Options- A. secondary current increase causes a primary current decrease
- B. primary current is increased by an increase in secondary current
- C. primary current is decreased by an increase in secondary current
- D. secondary current decrease causes a primary current increase Discuss
Correct Answer: primary current is increased by an increase in secondary current
- 10. When used as a filter, an inductor is
Options- A. placed in series with the load and aids any current changes
- B. placed in parallel with the load and aids any current changes
- C. placed in parallel with the load and opposes any current changes
- D. placed in series with the load and opposes any current changes Discuss
Correct Answer: placed in series with the load and opposes any current changes
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