Objective Questions on Transformers with Answers - Set 04 - ObjectiveBooks

Objective Questions on Transformers with Answers - Set 04

Practice Test: Question Set - 04


1. In a power or distribution transformer about 10 per cent end turns are heavily insulated
    (A) To withstand the high voltage drop due to line surge produced by the shunting capacitance of the end turns
    (B) To absorb the line surge voltage and save the winding of transformer from damage
    (C) To reflect the line surge and save the winding of a transformer from damage
    (D) None of the above

2. The turns ratio required to match an 80 Ω source to a 320 Ω load is
    (A) 80
    (B) 20
    (C) 4
    (D) 2

3. A good voltage regulation of a transformer means
    (A) Output voltage fluctuation from no load to full load is least
    (B) Output voltage fluctuation with power factor is least
    (C) Difference between primary and secondary voltage is least
    (D) Difference between primary and secondary voltage is maximum

4. Which of the following loss in a transformer is zero even at full load?
    (A) Core loss
    (B) Friction loss
    (C) Eddy current loss
    (D) Hysteresis loss

5. A no-load test is performed on a transformer to determine
    (A) Core loss
    (B) Copper loss
    (C) Efficiency
    (D) Magnetizing current and loss

6. 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

7. A step-down transformer has a turn’s ratio less than 1.
    (A) True
    (B) False

8. A center tap (CT) is a connection at the midpoint of the secondary winding of a transformer.
    (A) True
    (B) False

9. The efficiencies of transformers compared with that of electric motors of the same power are
    (A) About the same
    (B) Much smaller
    (C) Much higher
    (D) Somewhat smaller

10. Primary winding of a transformer
    (A) Is always a low voltage winding
    (B) Is always a high voltage winding
    (C) Could either be a low voltage or high voltage winding
    (D) None of the above

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