Transformers MCQ Questions - Set 07 - ObjectiveBooks
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# Practice Test: Question Set - 07

1. In a step-down transformer, there is a change of 15 A in the load current. This results in change of supply current of
(A) Less than 15 A
(B) More than 15 A
(C) 15 A
(D) None of the above

2. 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?
(A) 8
(B) 0.8
(C) 0.08
(D) 80

3. A step-up transformer steps up power.
(A) True
(B) False

4. Which of the following insulating materials can withstand the highest temperature safely?
(A) Cellulose
(B) Asbestos
(C) Mica
(D) Glass fibre

5. The primary winding of a transformer has 110 V ac across it. What is the secondary voltage if the turns ratio is 8?
(A) 8.8 V
(B) 88 V
(C) 880 V
(D) 8,800 V

6. In a transformer the resistance between its primary and secondary should be
(A) Zero
(B) 10 Q
(C) 1000 Q
(D) Infinity

7. A transformer transforms
(A) Voltage
(B) Current
(C) Current and voltage
(D) Power

8. For the parallel operation of single phase transformers it is necessary that they should have
(A) Same efficiency
(B) Same polarity
(C) Same kVA rating
(D) Same number of turns on the secondary side

9. Negative voltage regulation is indicative that the load is
(A) Capacitive only
(B) Inductive only
(C) Inductive or resistive
(D) None of the above

10. The efficiency of a transformer will be maximum when
(A) Copper losses = hysteresis losses
(B) Hysteresis losses = eddy current losses
(C) Eddy current losses = copper losses
(D) Copper losses = iron losses

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