Which of the following rectifiers have been used extensively in supplying direct current for electroplating ?

Related Mcqs:

1. The metal rectifiers are preferred to valve rectifiers due to which of the following advantages ?

   A. They are mechanically strong
   B. They do not require any voltage for filament heating
   C. Both (A) and (B)
   D. None of the above

2. Which of the following rectifiers are primarily used for charging of low voltage batteries from AC supply ?

   A. Mechanical rectifiers
   B. Copper oxide rectifiers
   C. Selenium rectifiers
   D. Electrolytic rectifiers
   E. Mercury arc rectifiers

3. In selenium rectifiers efficiencies ranging from _______ to _______ percent are attainable?

   A. 25, 35
   B. 40, 50
   C. 60, 70
   D. 75, 85

4. The applications of selenium rectifiers are usually limited to potential of_____________?

   A. 10 V
   B. 30 V
   C. 60 V
   D. 100 V
   E. 200 V

5. 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

6. 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

7. In a three-phase mercury arc rectifiers each anode conducts for____________?

   A. one-third of a cycle
   B. one-fourth of a cycle
   C. one-half a cycle
   D. two-third of a cycle

8. Glass rectifiers are usually made into units capable of D.C. output (maximum continuous rating) of _____________?

   A. 100 A at 100 V
   B. 200 A at 200 V
   C. 300 A at 300 V
   D. 400 A at 400 V
   E. 500 A at 500 V

9. Mercury, in arc rectifiers, is chosen for cathode because________________?

   A. its ionization potential is relatively low
   B. its atomic weight is quite high
   C. its boiling point and specific heat are low
   D. it remains in liquid state at ordi¬nary temperature
   E. all of the above

10. In which of the following equipment direct current is needed ?

    A. Telephones
    B. Relays
    C. Time switches
    D. All of the above