Rectifier Multiple Choice Questions and Answers

6.  Mercury, in arc rectifiers, is chosen for cathode because

   A. It's ionization potential is relatively low

   B. Its atomic weight is quite high

   C. Its boiling point and specific heat are low

   D. All of the above

7.  The cathode voltage drop in a mercury arc rectifier is due to

   A. Expenditure of energy in ionization

   B. Surface resistance

   C. Expenditure of energy in over-coming the electrostatic field

   D. Expenditure of energy in liberating electrons from the mercury

8.  The advantages of mercury arc rectifier is that

   A. It is light in weight and occupies small floor space

   B. It has high efficiency

   C. It has high overload capacity

   D. All of the above

9.  The potential drop in the arc in a mercury arc rectifier varies

   A. 0.05 to 0.2 V per cm length of the arc

   B. 0.5 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

10.  If cathode and anode connections in a mercury arc rectifier are interchanged

   A. The rectifier will not operate

   B. Internal losses will be reduced

   C. Both ion and electron streams will move in the same direction

   D. The rectifier will operate at reduced efficiency

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