Practice Test: Question Set - 05
1. In a transformer routine efficiency depends upon
- (A) Supply frequency
- (B) Load current
- (C) Power factor of load
- (D) Both (B) and (C)
2. When a 6 V battery is connected across the primary of a transformer with a turns ratio of 8, the secondary voltage is
- (A) 0 V
- (B) 6 V
- (C) 48 V
- (D) 0.75 V
3. Greater the secondary leakage flux
- (A) Less will be the secondary induced e.m.f.
- (B) Less will be the primary induced e.m.f.
- (C) Less will be the primary terminal voltage
- (D) None of the above
4. The chemical used in breather is
- (A) Asbestos fiber
- (B) Silica sand
- (C) Sodium chloride
- (D) Silica gel
5. A reflective load is a load as it appears to the source in the primary of a transformer.
- (A) True
- (B) False
6. The main reason for generation of harmonics in a transformer could be
- (A) Fluctuating load
- (B) Poor insulation
- (C) Mechanical vibrations
- (D) Saturation of core
7. A transformer can have zero voltage regulation at
- (A) Leading power factor
- (B) Lagging power factor
- (C) Unity power factor
- (D) Zero power factor
8. When the turns ratio of a transformer is 20 and the primary ac voltage is 12 V, the secondary voltage is
- (A) 12 V
- (B) 120 V
- (C) 240 V
- (D) 2,400 V
9. During short circuit test iron losses are negligible because
- (A) The current on secondary side is negligible
- (B) The voltage on secondary side does not vary
- (C) The voltage applied on primary side is low
- (D) Full-load current is not supplied to the
transformer
10. Iron loss of a transformer can be measured by
- (A) Low power factor wattmeter
- (B) Unity power factor wattmeter
- (C) Frequency meter
- (D) Any type of wattmeter
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