Q.1
In a transformer if the frequency of the supply is varied then the magnetizing current in the core also varies.
  • a) True
  • b) False
Q.2
CRGO Laminations in a transformer are used to minimize __________
  • a) eddy current loss
  • b) hysteresis loss
  • c) both eddy current and hysteresis loss
  • d) ohmic loss
Q.3
A single phase transformer has emf per turn having 2310/V, 50Hz transformer asV. Then the estimated primary turns will be?
  • a) 189 turns
  • b) 179 turns
  • c) 176 turns
  • d) 190 turns
Q.4
A single phase transformer has emf per turn having 2310/V, 50Hz transformer asV. The core area is(in square cm)?
  • a) 393
  • b) 277.8
  • c) 358.92
  • d) 450.03
Q.5
If a transformer is fed from a dc rather than a 1-phase ac supply, then the transformer will __________
  • a) burn its windings
  • b) operate normal
  • c) will not operate
  • d) will give very small leakage flux
Q.6
For a single phase transformer operating at normal operating conditions has useful flux of 1 Wb. If the machine is loaded at 0.8 p.f., then its mutual flux __________
  • a) may decrease to 0.98 Wb
  • b) remains constant
  • c) may increase 1.02 Wb
  • d) may decrease to 0.8 Wb
Q.7
The flux involved in the emf equation of a transformer has __________
  • a) rms value
  • b) average value
  • c) total value
  • d) maximum value
Q.8
If the frequency at the primary supply is varied gradually, then the secondary terminal voltage will __________
  • a) not change
  • b) vary directly
  • c) will vary oppositely
  • d) will vary inverse of frequency
Q.9
There are two identical transformers A and B such that flux density applied to B is doubled. Then magnetizing current of B is?
  • a) larger than A
  • b) double of A
  • c) half of A
  • d) same as that of A.
Q.10
A 20KVA, 2200/V,Hz single phase transformer has the below parameters:
  • a) 0.024 ‎Ω
  • b) 0.06 ‎Ω
  • c) 3 ‎Ω
  • d) 7 ‎Ω
Q.11
A 20KVA, 2200/V,Hz single phase transformer has the below parameters:
  • a) 0.024 ‎Ω
  • b) 0.06 ‎Ω
  • c) 3 ‎Ω
  • d) 7 ‎Ω
Q.12
A 20KVA, 2200/V,Hz single phase transformer has the below parameters:
  • a) 0.024 ‎Ω
  • b) 0.06 ‎Ω
  • c) 3 ‎Ω
  • d) 7 ‎Ω
Q.13
A 20KVA, 2200/V,Hz single phase transformer has the below parameters:
  • a) 0.024 ‎Ω
  • b) 0.06 ‎Ω
  • c) 3 ‎Ω
  • d) 7 ‎Ω
Q.14
In a transformer ______ decreases with increase of the leakage flux.
  • a) secondary terminal voltage
  • b) secondary induced voltage
  • c) primary induced voltage
  • d) all of the mentioned
Q.15
The components needed to draw the phasor diagram of the transformer is?
  • a) A, B, C
  • b) B
  • c) B, C
  • d) A, B
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