Electrical Engineering MCQ Question Papers: Campus Placement

Subject: Electrical Machine 2

**Part 2: List for questions and answers of Electrical Machine I**

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**Q1.What kVA rating is required for a transformer that must handle a maximum load current ****of 8 A with a secondary voltage of 2 kV?**

**a) 4kVA**

**b) 0.25kVA**

**c) 16kVA**

**d) 8kVA**

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**Q2.The turns ratio required to match an 80 source to a 320 load is**

**a) 80**

**b) 20**

**c) 4**

**d) 2**

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**Q3.When the turns ratio of a transformer is 20 and the primary ac voltage is 12 V, the ****secondary voltage is**

**a) 12V**

**b) 120V**

**c) 240V**

**d) 2,400V**

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**Q4.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?**

**a) 250**

**b) 25**

**c) 6,250**

**d) 62,500**

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**Q5.A certain transformer has 400 turns in the primary winding and 2,000 turns in the ****secondary winding. The turns ratio is**

**a) 0.2**

**b) 0.4**

**c) 5**

**d) 25 **

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**Q6.The primary winding of a transformer has 110 V ac across it.What is the secondary ****voltage if the turns ratio is 8?**

**a) 8.8V**

**b) 88V**

**c) 880V**

**d) 8,800V**

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**Q7.To step 110 V ac down to 20 V ac, the turns ratio must be**

**a) 5.5**

**b) 18**

**c) 0.18**

**d) 0.018**

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**Q8.The mutual inductance when k=0.65, L1=2H, and L2=5H is**

**a) 2mH**

**b) 2H**

**c) 4H**

**d) 8H**

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**Q9.If 25W of power are applied to the primary of an ideal transformer with a turns ratio of ****10, the power delivered to the secondary load is**

**a) 25W**

**b) 0W**

**c) 250W**

**d) 2.5W**

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**Q10.A transformer with a 110V primary has a 15:1 turns ratio. The load resistance, RL, is 120 ****.What is the approximate voltage across the load?**

**a) 7.3V**

**b) 73V**

**c) 88V**

**d) 880V**

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**Q11.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?**

**a) 9V**

**b) 90V**

**c) 900V**

**d) 0.9V **

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**Q12.In a certain loaded transformer, the secondary voltage is one-fourth the primary ****voltage. The secondary current is**

**a) One-fourth the primary current**

**b) Four times the primary current**

**c) Equal to the primary current**

**d) One-fourth the primary current and equal to the primary current**

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**Q13.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**

**a) 1.7 V**

**b) 0.85 V**

**c) 1 V**

**d) 0 V**

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**Q14.The primary coil of a transformer is connected to a 60 V ac source. The secondary coil is ****connected to a 330 load. The turns ratio is 3:1. What is the secondary voltage?**

**a) 2V**

**b) 20V**

**c) 180V**

**d) 18V**

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**Q15.The primary winding of a power transformer should always be**

**a) Open**

**b) Shorted**

**c) Switched**

**d) Fused**

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**Q16.A certain amplifier has 600 internal resistance looking from its output. In order to ****provide maximum power to a 4 speaker, what turns ratio must be used in the coupling ****transformer?**

**a) 8**

**b) 0.8**

**c) 0.08**

**d) 80**

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**Q17.A transformer**

**a) Changes ac to dc**

**b) Changes dc to ac**

**c) Steps up or down dc voltages**

**d) Steps up or down ac voltages **

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**Q18.The primary of a transformer is connected to a 6 V battery. The turns ratio is 1:3 and ****the secondary load, RL, is 100 . The voltage across the load is**

**a) 0V**

**b) 6V**

**c) 18V**

**d) 2V**

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**Q19.To step 120 V ac up to 900 V ac, the turns ratio must be**

**a) 75**

**b) 750**

**c) 7.5**

**d) 0.13**

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**Q20.When a 200 load resistor is connected across the secondary winding of a transformer ****with a turns ratio of 4, the source “sees” a reflective load of**

**a) 50**

**b) 12.5**

**c) 800**

**d) 0 **

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**Part 2: List for questions and answers of Electrical Machine I**

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**Q1. Answer: c**

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**Q2. Answer: d**

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**Q3. Answer: c**

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**Q4. Answer: c**

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**Q5. Answer: c**

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**Q6. Answer: c**

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**Q7. Answer: c**

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**Q8. Answer: b**

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**Q9. Answer: a**

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**Q10. Answer: a**

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**Q11. Answer: b**

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**Q12. Answer: b**

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**Q13. Answer: a**

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**Q14. Answer: b**

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**Q15. Answer: d**

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**Q16. Answer: c**

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**Q17. Answer: d**

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**Q18. Answer: a**

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**Q19. Answer:**

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**Q20. Answer: b**