Transformers problems
- 1. When does maximum power transfer happen from the source to the load?
Options- A. When the source resistance is greater than the load resistance
- B. When the source resistance is less than the load resistance
- C. When there is negligible source resistance
- D. When the source resistance equals the load resistance Discuss
Correct Answer: When the source resistance equals the load resistance
- 2. If the primary power of an ideal transformer having a 2:1 voltage ratio is 100 W, the secondary power is
Options- A. 100 W
- B. 50 W
- C. 75 W
- D. 200 W Discuss
Correct Answer: 100 W
- 3. A transformer is plugged into a 120 V rms source and has a primary current of 300 mA rms. The secondary is providing 18 V across a 10 Ω load. What is the efficiency of the transformer?
Options- A. 88%
- B. 90%
- C. 92%
- D. 95% Discuss
Correct Answer: 90%
- 4. The transformer turns ratio determines
Options- A. the ratio of primary and secondary voltages
- B. the ratio of primary and secondary currents
- C. the reflected impedance
- D. all of the above Discuss
Correct Answer: all of the above
- 5.
In the given circuit, the secondary voltage is in phase with the primary voltage.
Options- A. True
- B. False Discuss
Correct Answer: True
- 6. Regardless of whether the transformer is step-up or step-down, power in the primary equals the power in the secondary if there is 100% efficiency.
Options- A. True
- B. False Discuss
Correct Answer: True
- 7. The reflected load value that the source sees will always be larger than the load value itself.
Options- A. True
- B. False Discuss
Correct Answer: False
- 8. If the current drawn in the secondary of a transformer increases, the power in the primary should remain the same.
Options- A. True
- B. False Discuss
Correct Answer: False
- 9. The secondary voltages produced by a center-tapped transformer are equal in amplitude but 180° out of phase with respect to the center tap.
Options- A. True
- B. False Discuss
Correct Answer: True
- 10. An open secondary winding of a transformer will cause the primary current to be nearly zero.
Options- A. True
- B. False Discuss
Correct Answer: True
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