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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