Q.1
All changes in the state of matter of a substance requires a change in
  • mass
  • temperature
  • permission
  • energy
Q.2
Identify the correct order for the voltage transformation for the three-phase transformers.
  • D-Y > D-D = Y-Y > Y-D
  • D-Y > D-D > Y-Y > Y-D
  • D-Y > D-D = Y-Y < Y-D
  • D-Y > D-D < Y-Y < Y-D
Q.3
For a star-delta three phase transformer, if the transformation ratio is ‘x:1’, then how much percent of output will be?
  • 73%
  • 57%
  • 173%
  • 157%
Q.4
For a delta-star three phase transformer, if the transformation ratio is ‘x:1’, then how much percent of output will be improved?
  • 73%
  • 57%
  • 173%
  • 157%
Q.5
In three phase supply, the voltage phases are displaced by ________ and in two phase by ___________
  • 120°, 90°
  • 180°, 90°
  • 120, 120°
  • 120°, 180°
Q.6
Operating transformers in parallel gives the advantage of ___________
  • reliable loading
  • increased capacity of power system
  • reducing the capacity of substation
  • all of the mentioned
Q.7
Two single phase transformers A and B are operating in parallel having same impedance. But the x/r ratio of them are not equal and xa > xb. Then?
  • A has poorer pf than B
  • B has poorer pf than B
  • lesser power factor angle
  • both operate at same power factor
Q.8
Two single phase transformers A and B are operating in parallel having same impedance. But the x/r ratio of them are not equal. Then total kVA output of the output will be ___________
  • less than sum of kVA of A and B
  • more than sum of kVA of A and B
  • equal to sum of kVA of A and B
  • any of the mentioned
Q.9
Which of the following is the correct matching made for the harmonics and the associated harmonic component?A. Positive sequence components - 5th harmonic componentB. Negative sequence components - 7th harmonic componentC. Zero sequence components - 3rd harmonic component
  • A, B, C
  • C
  • A, B
  • B, C
Q.10
Which if the conditions is must be fulfilled for satisfactory parallel operation of transformers?
  • Same voltage ratio
  • Leakage impedances should be inversely proportional to kVA of the transformer
  • Same pu impedance
  • Correct polarity
Q.11
A 2000/1000/three winding transformer is to be used as auto transformer with supply ofV. Two loads ofkVA atand other one atkVA at 1000V. The total kVA supplied will be?
  • 1230 kVA
  • 1440 kVA
  • 1680 kVA
  • 1150 kVA
Q.12
Transformer operating in parallel will share a common load in the best possible manner if ____________
  • leakage impedances are proportional to their kVA rating
  • pu leakage impedances are equal
  • leakage impedances are equal
  • any of the mentioned
Q.13
What is the phase change of a solid to a liquid?
  • freezing
  • melting
  • boiling
  • condensation
Q.14
What is it called when a solid turns directly into a gas?
  • Sublimation
  • Condensation
  • Liquid
  • deposition
Q.15
Change from gas to liquid...
  • condensation
  • evaporation
  • expansion
  • movement
Q.16
Change from Liquid to Solid is call......
  • fusion
  • Freezing
  • sublimation
  • evaporation
Q.17
What is deposition?
  • Phase change from gas to solid
  • phase change from liquid to solid
  • Phase change from solid to gas
  • Phase change from liquid to gas
Q.18
Change from liquid to gas is called....
  • expansion
  • evaporation
  • condensation
  • sublimation
Q.19
During a phase change what happens to temperature?
  • it increases
  • it decreases
  • depends; if being heated it increases, if being cooled it decreases
  • stays constant
Q.20
What is sublimation?
  • phase change between solid and liquid
  • pahse change from gas to solid
  • phase change from solid to gas
  • phase change from solid to solid
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