1. In a transformer, the power factor of no-load current is
(a) high.
(b) unity.
(c) small.
(d) zero.
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2. The power factor of a power transformer on on-load is nearly
(a) zero.
(b) 0.75.
(c) 0.35.
(d) unity.
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3. The chemical used in breather is
(a) silica gel.
(b) potassium carbonate.
(c) sodium carbide.
(d) transformer oil.
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4. When the leakage flux in a transformer increases, it will decrease the
(a) primary induced emf.
(b) secondary induced emf.
(c) secondary terminal voltage.
(d) all of the above.
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5. While conducting short-circuit test on a transformer which side prefer to be short circuited?
(a) High voltage side.
(b) Low voltage side.
(c) Primary side.
(d) Secondary side.
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6. When the supply frequency of a transformer is increased by double, then its eddy current losses will
(a) double.
(b) four times.
(c) eight times.
(d) remain same.
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7. While conducting open circuit test on a transformer which side prefer to be open?
(a) High voltage side.
(b) Low voltage side.
(c) Primary side.
(d) Secondary side.
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8. Which winding in a transformer has more number of turns?
(a) LV winding.
(b) HV winding.
(c) primary winding.
(d) secondary winding.
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9. If the secondary voltage of a transformer having turn ratio of 0.1 is 12V, the primary applied voltage must be
(a) 0.12 volt.
(b) 1.2 volt.
(c) 12 volt.
(d) 120 volt.
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10. Star-star transformers work satisfactorily when load is
(a) unbalanced.
(b) balanced.
(c) fluctuating.
(d) all of the above.
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11. Secondary winding of an auto transformer is also known as
(a) compensating winding.
(b) common winding.
(c) territory winding.
(d) high Voltage winding.
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12. The leakage flux in a transformer mainly depends upon
(a) load current.
(b) supply voltage.
(c) supply frequency.
(d) power factor.
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13. Air core Transformer as compared to iron core Transformer has
(a) more copper losses.
(b) less magnetic losses.
(c) more magnetic losses.
(d) no magnetic losses.
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14. The path of the magnetic flux in transformer should have
(a) high reluctance.
(b) low reluctance.
(c) high resistance.
(d) low resistance.
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15. The purpose of using CRGO steel for the core of transformer is to reduce
(a) eddy current losses.
(b) hysteresis losses.
(c) copper losses.
(d) all of the above.
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