Rectifiers And Converters(Electrical Engineering ) Questions and Answers

Question 1. The advantage of mercury arc rectifier is that
  1.    it is light in weight and occupies small floor space
  2.    it has high efficiency
  3.    it has high overload capacity
  4.    it is comparatively noiseless
  5.    all of the above
Explanation:-
Answer: Option E. -> all of the above
Question 2. The metal rectifiers, as compared to mercury arc rectifiers
  1.    operate on low temperatures
  2.    can operate on high voltages
  3.    can operate on heavy loads
  4.    give poor regulation
  5.    none of the above
Explanation:-
Answer: Option A. -> operate on low temperatures
Question 3. In a mercury arc rectifier positive ions are attracted towards
  1.    anode
  2.    cathode
  3.    shell bottom
  4.    mercury pool
Explanation:-
Answer: Option B. -> cathode
Question 4. The potential drop in the arc, in a mercury arc rectifier, varies
  1.    0.05 V to 0.2 V per cm length of the arc
  2.    0.5 V to 1.5 V per cm length of the arc
  3.    2 V to 3.5 V per cm length of the arc
  4.    none of the above
Explanation:-
Answer: Option D. -> none of the above
Question 5. In selenium rectifiers efficiencies ranging from ______ to ______ percent are attainable
  1.    25, 35
  2.    40, 50
  3.    60, 70
  4.    75, 85
Explanation:-
Answer: Option D. -> 75, 85
Question 6. 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 7. 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 8. 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 9. 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 10. 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
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