Objective type Questions and Answers on Transformers - Set 02 - ObjectiveBooks

# Practice Test: Question Set - 02

1. Which of the following properties is not necessarily desirable for the material for transformer core?
(A) Low hysteresis loss
(B) High permeability
(C) High thermal conductivity

2. Gas is usually not liberated due to dissociation of transformer oil unless the oil temperature exceeds
(A) 50°C
(B) 80°C
(C) 100°C
(D) 150°C

3. Material used for construction of transformer core is usually
(A) Wood
(B) Copper
(C) Aluminium
(D) Silicon steel

4. 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

5. The mutual inductance when k = 0.65, L1 = 2 Î¼H, and L2 = 5 Î¼H is
(A) 2 mH
(B) 2 Î¼H
(C) 4 Î¼H
(D) 8 Î¼H

6. 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) 4 kVA
(B) 0.25 kVA
(C) 16 kVA
(D) 8 kVA

7. If the percentage impedances of the two transformers working in parallel are different, then
(A) Transformers will be overheated
(B) Power factors of both the transformers will be same
(C) Parallel operation will be not possible
(D) Parallel operation will still be possible, but the power factors at which the two transformers operate will be different from the power factor of the common load

8. A transformer consists of two or more cores that are electrically coupled on a common core.
(A) True
(B) False

9. If the voltage is stepped up, the current is stepped down, and vice versa.
(A) True
(B) False

10. A transformer oil must be free from
(A) Sludge
(B) Odour
(C) Gases
(D) Moisture

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