MCQGeeks
0 : 0 : 1
CBSE
JEE
NTSE
NEET
English
UK Quiz
Quiz
Driving Test
Practice
Games
Quiz
Electrical Engineering
Transformers
Quiz 3
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
Q.1
The thickness of laminations used in a transformer is usually
0.4 mm to 0.5 mm
4 mm to 5 mm
14 mm to 15 mm
25 mm to 40 mm
Q.2
Minimum voltage regulation occurs when the power factor of the load is
unity
lagging
leading
zero
Q.3
The highest voltage for transmitting electrical power in India is
33 kV
66 kV
132 kV
400 kV
Q.4
The chemical used in breather is
asbestos fiber
silica sand
sodium chloride
silica gel
Q.5
The no-load current drawn by transformer is usually what per cent of the full-load current?
0.2 to 0.5 per cent
2 to 5 per cent
12 to 15 per cent
20 to 30 per cent
Q.6
The chemical used in breather for transformer should have the quality of
ionizing air
absorbing moisture
cleansing the transformer oil
cooling the transformer oil
Q.7
The full-load copper loss of a transformer is 1600 W. At half-load, the copper loss will be
6400 W
1600 W
800 W
400 W
Q.8
The size of a transformer core will depend on
frequency
area of the core
flux density of the core material
(A) and (B) both
Q.9
Delta/star transformer works satisfactorily when
load is balanced only
load is unbalanced only
on balanced as well as unbalanced loads
none of the above
Q.10
The purpose of providing an iron core in a transformer is to
provide support to windings
reduce hysteresis loss
decrease the reluctance of the magnetic path
reduce eddy current losses
Q.11
A good voltage regulation of a transformer means
output voltage fluctuation from no load to full load is least
output voltage fluctuation with power factor is least
difference between primary and secondary voltage is least
difference between primary and secondary voltage is maximum
Q.12
The function of conservator in a transformer is
to project against internal fault
to reduce copper as well as core losses
to cool the transformer oil
to take care of the expansion and contraction of transformer oil due to variation of temper-ature of sur-roundings
Q.13
The function of breather in a transformer is
to provide oxygen inside the tank
to cool the coils during reduced load
to cool the transformer oil
to arrest flow of moisture when outside air enters the transformer
Q.14
A transformer cannot raise or lower the voltage of a D.C. supply because
There is no need to change the D.C. voltage
A D.C. circuit has more losses
Faraday's laws of electromagnetic induction are not valid since the rate of change of flux is zero
None of the above
Q.15
Which of the following loss in a transformer is zero even at full load ?
Core loss
Friction loss
Eddy current loss
Hysteresis loss
Q.16
If the percentage impedances of the two transformers working in parallel are different, then
transformers will be overheated
power factors of both the transformers will be same
parallel operation will be not possible
parallel operation will still be possible, but the power factors at which the two transformers operate will be different from the power factor of the common load
Q.17
An ideal transformer will have maximum efficiency at a load such that
copper loss = iron loss
copper loss < iron loss
copper loss > iron loss
none of the above
Q.18
Two transformers are connected in parallel. These transformers do not have equal percentage impedance. This is likely to result in
short-circuiting of the secondaries
power factor of one of the transformers is leading while that of the other lagging
transformers having higher copper losses will have negligible core losses
loading of the transformers not in proportion to their kVA ratings
Q.19
Part of the transformer which is most subject to damage from overheating is
iron core
copper winding
winding insulation
frame or case
Q.20
A Buchholz relay can be installed on
auto-transformers
air-cooled transformers
welding transformers
oil cooled transformers
Q.21
What will happen if the transformers working in parallel are not connected with regard to polarity?
The power factor of the two transformers will be different from the power factor of common load
Incorrect polarity will result in dead short circuit
The transformers will not share load in proportion to their kVA ratings
none of the above
Q.22
The path of a magnetic flux in a transformer should have
high resistance
high reluctance
low resistance
low reluctance
Q.23
The path of the magnetic flux in transformer should have
high reluctance
low reactance
high resistance
low resistance
Q.24
Which of the following is the most likely source of harmonics in a transformer?
poor insulation
Overload
loose connections
Core saturation
Q.25
The leakage flux in a transformer depends upon
load current
load current and voltage
load current, voltage and frequency
load current, voltage, frequency and power factor
Q.26
Reduction in core losses and increase in permeability are obtained with transformer employing
core built-up of laminations of cold rolled grain oriented steel
core built-up of laminations of hot rolled sheet
either of the above
none of the above
Q.27
Harmonics in transformer result in
increased core losses
increased I2R losses
magnetic interference with communication circuits
all of the above
Q.28
Transformer breaths in when
load on it increases
load on it decreases
load remains constant
none of the above
Q.29
Material used for construction of transformer core is usually
wood
copper
aluminium
silicon steel
Q.30
Natural oil cooling is used for transformers up to a rating of
3000 kVA
1000 kVA
500 kVA
250 kVA
0 h : 0 m : 1 s
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
Report Question
×
What's an issue?
Question is wrong
Answer is wrong
Other Reason
Want to elaborate a bit more? (optional)
Support mcqgeeks.com by disabling your adblocker.
×
Please disable the adBlock and continue.
Thank you.
Reload page