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- Question
A transformer
Options- A. changes ac to dc
- B. changes dc to ac
- C. steps up or down dc voltages
- D. steps up or down ac voltages
- Correct Answer
- steps up or down ac voltages
- 1. The turns ratio required to match an 80 Ω source to a 320 Ω load is
Options- A. 80
- B. 20
- C. 4
- D. 2 Discuss
- 2. The mutual inductance when k = 0.65, L1 = 2 µH, and L2 = 5 µH is
Options- A. 2 mH
- B. 2 µH
- C. 4 µH
- D. 8 µH Discuss
- 3. A certain amplifier has 600 Ω internal resistance looking from its output. In order to provide maximum power to a 4 Ω speaker, what turns ratio must be used in the coupling transformer?
Options- A. 8
- B. 0.8
- C. 0.08
- D. 80 Discuss
- 4. To step 120 V ac up to 900 V ac, the turns ratio must be
Options- A. 75
- B. 750
- C. 7.5
- D. 0.13 Discuss
- 5. If a transformer has 50 turns in the primary winding and 10 turns in the secondary winding, what is the reflective resistance if the secondary load resistance is 250 Ω?
Options- A. 250 Ω
- B. 25 Ω
- C. 6,250 Ω
- D. 62,500 Ω Discuss
- 6. The primary winding of a power transformer should always be
Options- A. open
- B. shorted
- C. switched
- D. fused Discuss
- 7. The primary coil of a transformer is connected to a 60 V ac source. The secondary coil is connected to a 330 Ω load. The turns ratio is 3:1. What is the secondary voltage?
Options- A. 2 V
- B. 20 V
- C. 180 V
- D. 18 V Discuss
- 8. How many primary volts must be applied to a transformer with a turns ratio of 0.1 to obtain a secondary voltage of 9 V?
Options- A. 9 V
- B. 90 V
- C. 900 V
- D. 0.9 V Discuss
- 9. A certain transformer has 400 turns in the primary winding and 2,000 turns in the secondary winding. The turns ratio is
Options- A. 0.2
- B. 0.4
- C. 5
- D. 25 Discuss
- 10. A certain transformer has a turns ratio of 1 and a 0.85 coefficient of coupling. When 2 V ac is applied to the primary, the secondary voltage is
Options- A. 1.7 V
- B. 0.85 V
- C. 1 V
- D. 0 V Discuss
Transformers problems
Search Results
Correct Answer: 2
Correct Answer: 2 µH
Correct Answer: 0.08
Correct Answer: 7.5
Correct Answer: 6,250 Ω
Correct Answer: fused
Correct Answer: 20 V
Correct Answer: 90 V
Explanation:
We know that, V2/V1 = N2/N1.
Given V2 = 9v, N2/N1 = 0.1
Therefore, 9v/V1 = 0.1
V1 = 9v/0.1 = 90v.
Given V2 = 9v, N2/N1 = 0.1
Therefore, 9v/V1 = 0.1
V1 = 9v/0.1 = 90v.
For more detail: Step Down Transformer - Circuit with Simulation.
Correct Answer: 5
Correct Answer: 1.7 V
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