Transformer Objective Questions and Answers pdf free - Set 10 - ObjectiveBooks

# Practice Test: Question Set - 10

1. 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

2. Sumpner's test is conducted on transformers to determine
(A) Temperature
(B) Stray losses
(C) All-day efficiency
(D) None of the above

3. Which winding in a transformer has more number of turns?
(A) Low voltage winding
(B) High voltage winding
(C) Primary winding
(D) Secondary winding

4. Power transformers are designed to have maximum efficiency at

5. What will happen if the transformers working in parallel are not connected with regard to polarity?
(A) The power factor of the two transformers will be different from the power factor of common load
(B) Incorrect polarity will result in dead short circuit
(C) The transformers will not share load in proportion to their kVA ratings
(D) None of the above

6. 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

7. An ideal transformer has infinite values of primary and secondary inductances. The statement is
(A) True
(B) False

8. A Buchholz relay can be installed on
(A) Auto-transformers
(B) Air-cooled transformers
(C) Welding transformers
(D) Oil cooled transformers

9. The core used in high frequency transformer is usually
(A) Copper core
(B) Cast iron core
(C) Air core
(D) Mild steel core

10. An ideal transformer is one which has
(A) No losses and magnetic leakage
(B) Interleaved primary and secondary windings
(C) A common core for its primary and secondary windings
(D) Core of stainless steel and winding of pure copper metal

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