Q.1
Which of the following rectifiers are primarily used for charging of low voltage batteries from AC. supply?
Q.2
The efficiency of the copper oxide rectifier seldom exceeds
Q.3
In a mercury arc rectifier______ flow from anode to cathode
Q.4
The voltage drop at anode, in a mercury arc rectifier is due to
Q.5
To produce cathode spot in a mercury arc rectifier
Q.6
A synchronous converter can be started
Q.7
In a mercury pool rectifier, the voltage drop across its electrodes
Q.8
When a rectifier is loaded which of the following voltage drops take place ?
Q.9
In a mercury arc rectifier characteristic blue luminosity is due to
Q.10
In a phase-shift control method, the phase shift between anode and grid voltages can be achieved by means of
Q.11
On which of the following factors the number of phases for which a rectifier should be designed depends?
Q.12
With a motor converter it is possible to obtain D.C. voltage only upto
Q.13
A rotary converter combines the function of
Q.14
The efficiency of an electrolytic rectifier is nearly
Q.15
A rotary converter is a single machine with
Q.16
In a single phase rotary converter the number of slip rings will be
Q.17
A commutating rectifier consists of commutator driven by
Q.18
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.
Q.19
Which of the following mercury arc rectifier will deliver least undulating current?
Q.20
Which of the following rectifiers have been used extensively in supplying direct current for electroplating?
Q.21
In a three-phase mercury arc rectifiers each anode conducts for
Q.22
Which of the following metals is generally manufactured by electrolysis process?
Q.23
If cathode and anode connections in a mercury arc rectifier are inter changed
Q.24
A rotary converter operates at a
  • low power factor
  • high power factor
  • zero power factor
  • none of the above
Q.25
Which of the following is reversible in action?
  • Motor generator set
  • Motor converter
  • Rotary converter
  • Any of the above
  • E. None of the above
Q.26
Selenium rectifier can be operated at temperatures as high as
  • 25°C
  • 40°C
  • 60°C
  • 75°C
Q.27
The ionization potential of mercury is approximately
  • 5.4 V
  • 8.4 V
  • 10.4 V
  • 16.4 V
Q.28
A mercury arc rectifier possesses ________ regulation characteristics
  • straight line
  • curved line
  • exponential
  • none of the above
Q.29
In phase-shift control method the control is carried out by varying the of grid voltage.
  • magnitude
  • polarity
  • phase
  • any of the above
  • E. none of the above
Q.30
In which of the following appUcations, direct current is absolutely essential ?
  • Illumination
  • Electrolysis
  • Variable speed operation
  • Traction
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