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.Management Sciences
Category: Rectifiers and Converters
With a motor converter it is possible to obtain D.C. voltage only upto__________?
A. 200-100 V
B. 600—800 V
C. 1000—1200 V
D. 1700—2000 V
The cathdde voltage drop, in a mercury arc rectifier, is due to_____________?
A. expenditure of energy in ionization
B. surface resistance
C. expenditure of energy in overcoming the electrostatic field
D. expenditure of energy in liberating electrons from the mercury
In mercury arc rectifiers having grid, the arc can be struck between anode and cathode only when the grid attains a certain potential, this potential being known as______________?
A. maximum grid voltage
B. critical grid voltage
C. any of the above
D. none of the above
The potential drop in the arc, in a mercury arc rectifier, varies_____________?
A. 0.05 V to 0.2 V per cm length of the arc
B. 0.5 V to 1.5 V per cm length of the arc
C. 2 V to 3.5 V per cm length of the arc
D. none of the above
A rotary converter in general construction and design, is more or less like___________?
A. a transformer
B. an induction motor
C. an alternator
D. any D.C. machine
In which of the following appUcations, direct current is absolutely essential ?
A. Illumination
B. Electrolysis
C. Variable speed operation
D. Traction
In a grid control of mercury arc rectifiers when the grid is made positive relative to cathode, then it the electrons on their may to anode.
A. accelerates
B. decelerates
C. any of the above
D. none of the above
In a mercury arc rectifier characteristic blue luminosity is due to_____________?
A. colour of mercury
B. ionization
C. high temperature
D. electron streams
Which of the following statement is incorrect ?
A. Copper oxide rectifier is a linear device
B. Copper oxide rectifier is not a perfect rectifier
C. Copper oxide rectifier has a low efficiency
D. Copper oxide rectifier finds use in control circuits
E. Copper oxide rectifier is not stable during early life
In a phase-shift control method, the phase shift between anode and grid voltages can be achieved by means of______________?
A. shunt motor
B. synchronous motor
C. induction regulator
D. synchronous generator
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