In a mercury arc rectifier characteristic blue luminosity is due to_____________?

Related Mcqs:

1. The voltage drop at anode, in a mercury arc rectifier is due to_____________?

   A. self restoring property of mercury
   B. high ionization potential
   C. energy spent in overcoming the electrostatic field
   D. high temperature inside the rectifier

2. The cathdde voltage drop, in a mercury arc rectifier, is due to_____________?

   A. expenditure of energy in ionization
   B. surface resistance
   C. expenditure of energy in overcoming the electrostatic field
   D. expenditure of energy in liberating electrons from the mercury

3. The potential drop in the arc, in a mercury arc rectifier, varies_____________?

   A. 0.05 V to 0.2 V per cm length of the arc
   B. 0.5 V 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

4. The ignited or auxiliary anode in mercury arc rectifier is made of____________?

   A. graphite
   B. boron carbide
   C. aluminium
   D. copper

5. Which of the following is the loss within the mercury arc rectifier chamber ?

   A. Voltage drop in arc
   B. Voltage drop at the anode
   C. Voltage drop at the cathode
   D. All of the above

6. Which of the following mercury arc rectifier will deliver least undulating current?

   A. Six-phase
   B. Three-phase
   C. Two-phase
   D. Single-phase

7. The voltage drop between the anode and cathode, of a mercury arc rectifier comprises of the following_____________?

   A. anode drop and cathode drop
   B. anode drop and arc drop
   C. cathode drop and arc drop
   D. anode drop, cathode drop and arc drop

8. The internal efficiency of a mercury arc rectifier depends on___________?

   A. voltage only
   B. current only
   C. voltage and current
   D. r.m.s. value of current
   E. none of the above

9. The advantage 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. it is comparatively noiseless
   E. all of the above

10. In a mercury arc rectifier positive ions are attracted towards______________?

    A. anode
    B. cathode
    C. shell bottom
    D. mercury pool