Related Questions

The major reason of hydrodynamic noise (i.e., noise resulting from liquid flow) is
A Pipe vibrations
B Cavitation
C Boundary layer separation
D Fluctuation in liquid flow
Aerodynamic noise resulting from turbulent gas flow is the most prevalent source of valve noise in fluid ilow control. It is caused due to
A Reynold stresses
B Shear forces
C Both A & B
D Neither A nor B
The noise resulting from vibrations of laminations set by magnetic forces, is termed as
A Magnetostriction
B Boo
C Hum
D Zoom
The materials which fracture even at small strains are termed as brittle, while those materials which exhibit an appreciable deformation before failure are termed as
A Rigid
B Tough
C Ductile
D Plastic
Noise level test in a transformer is a
A special test
B routine test
C type test
D none of the above
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

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