Practice Test: Question Set - 02
1. 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
2. When a rectifier is loaded which of the following voltage drops take place?
- (A) Voltage drop in transformer reactance
- (B) Voltage drop in resistance of transformer and
smoothing chokes
- (C) Arc voltage drop
- (D) All of the above
3. Which of the following mercury arc rectifier will deliver least undulating current?
- (A) Six-phase
- (B) Three-phase
- (C) Two-phase
- (D) Single-phase
4. 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 overcoming the
electrostatic field
- (D) Expenditure of energy in liberating
electrons from the mercury
5. 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
6. In a mercury arc rectifier positive ions are attracted towards
- (A) Anode
- (B) Cathode
- (C) Shell bottom
- (D) Mercury pool
7. A rotary converter operates at a
- (A) Low power factor
- (B) High power factor
- (C) Zero power factor
- (D) None of the above
8. Which of the following are the applications of D.C. system?
- (A) Battery charging work
- (B) Arc welding
- (C) Electrolytic and electrochemical processes
- (D) All of the above
9. A rotary converter is a single machine with
- (A) One armature and one field
- (B) Two armatures and one field
- (C) One armature and two fields
- (D) None of the above
10. The ionization potential of mercury is approximately
- (A) 5.4 V
- (B) 8.4 V
- (C) 10.4 V
- (D) 16.4 V
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