Rectifiers And Converters(Engineering > Electrical Engineering ) Questions and Answers

Question 1. In which of the following equipment direct current is needed?
  1.    Telephones
  2.    Relays
  3.    Time switches
  4.    All of the above
Explanation:-
Answer: Option D. -> All of the above
Question 2. Mercury, in arc rectifiers, is chosen for cathode because
  1.    Its ionization potential is relatively low
  2.    Its atomic weight is quite high
  3.    Its boiling point and specific heat are low
  4.    All of the above
Explanation:-
Answer: Option D. -> All of the above
Question 3. It is the_______of the transformer on which the magnitude of angle of overlap depends.
  1.    resistance
  2.    capacitance
  3.    leakage reactance
  4.    any of the above
Explanation:-
Answer: Option C. -> leakage reactance
Question 4. Normally, which of the following is used, when a large-scale conversion from AC. to D.C. power is required?
  1.    Motor-generator set
  2.    Motor converter
  3.    Rotary converter
  4.    Mercury arc rectifier
Explanation:-
Answer: Option D. -> Mercury arc rectifier
Question 5. Which of the following is the loss within the mercury arc rectifier chamber?
  1.    Voltage drop in arc
  2.    Voltage drop at the anode
  3.    Voltage drop at the cathode
  4.    All of the above
Explanation:-
Answer: Option D. -> All of the above
Question 6. The voltage drop at anode, in a mercury arc rectifier is due to
  1.    self restoring property of mercury
  2.    high ionization potential
  3.    energy spent in overcoming the electrostatic field
  4.    high temperature inside the rectifier
Explanation:-
Answer: Option C. -> energy spent in overcoming the electrostatic field
Question 7. A rotary converter is a single machine with
  1.    one armature and one field
  2.    two armatures and one field
  3.    one armature and two fields
  4.    none of the above
Explanation:-
Answer: Option A. -> one armature and one field
Question 8. The efficiency of an electrolytic rectifier is nearly
  1.    80%
  2.    70%
  3.    60%
  4.    40%
Explanation:-
Answer: Option C. -> 60%
Question 9. Which of the following mercury arc rectifier will deliver least undulating current?
  1.    Six-phase
  2.    Three-phase
  3.    Two-phase
  4.    Single-phase
Explanation:-
Answer: Option A. -> Six-phase
Question 10. 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.
  1.    accelerates
  2.    decelerates
  3.    any of the above
  4.    none of the above
Explanation:-
Answer: Option A. -> accelerates
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