Related Questions

In an actual transformer the iron loss remains practically constant from noload to fullload because
A value of transformation ratio remains constant
B permeability of transformer core remains constant
C core flux remains practically constant
D primary voltage remains constant
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
The applied voltage of a certain transformer is increased by 50%, while the frequency is reduced by 50%. The maximum core flux density will
A become three times
B become 1.5 times
C become half
D remian the same
The effective resistance of an iron-cored choke working on ordinary supply frequency is more than its true resistance because of
A Iron loss in core
B Skin effect
C Increase in temperature
D Capacitive effect between adjacent coil turns
Which of the following is the main advantage of an auto-transformer over a two-winding transformer?
A Eddy losses are totally eliminated
B Copper losses are negligible
C Saving in winding material
D Hysteresis losses are reduced
The output transformer used in a power amplifier is a ___________ transformer
A 1:1 ratio
B Step-up
C Step-down
D None of the above
The changes in volume of transformer cooling oil due to variation of atmospheric tem-perature during day and night is taken care of by which part of transformer
A Conservator
B Breather
C Bushings
D Buchholz relay
Which of the following is the main advantage of an auto-transformer over a two winding transformer?
A Hysteresis losses are reduced
B Saving in winding material
C Copper losses are negligible
D Eddy losses are totally eliminated
Power amplifiers generally use transformer coupling because transformer per-mits
A Cooling of the circuit
B Impedance matching
C Distortionless output
D Good frequency response
A man spends 75% of his income. his income is increased by 20% and he increased his expenditure by 10%. His savings are increased by :
A 10%
B 25%
C 37.50%
D 50%

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