Practice Test: Question Set - 04
1. The metal rectifiers, as compared to mercury arc rectifiers
- (A) Operate on low temperatures
- (B) Can operate on high voltages
- (C) Can operate on heavy loads
- (D) Give poor regulation
2. Which of the following statement is incorrect?
- (A) Copper oxide rectifier is a linear device
- (B) Copper oxide rectifier is not a perfect rectifier
- (C) Copper oxide rectifier has a low efficiency
- (D) Copper oxide rectifier finds use in control
circuits
3. In a glass bulb mercury arc rectifier the maximum current rating is restricted to
- (A) 2000 A
- (B) 1500 A
- (C) 1000 A
- (D) 500 A
4. In a rotary converter I2R losses as compared to a D.C. generator of the same size will be
- (A) Same
- (B) Less
- (C) Double
- (D) Three times
5. With a motor converter it is possible to obtain D.C. voltage only upto
- (A) 100—200 V
- (B) 600—800 V
- (C) 1000—1200 V
- (D) 1700—2000 V
6. A synchronous converter can be started
- (A) By means of a small auxiliary motor
- (B) From AC. side as induction motor
- (C) From D.C. side as D.C. motor
- (D) Any of the above methods
7. In a rotary converter armature currents are
- (A) D.C. only
- (B) A.C. only
- (C) Partly A.C. and partly D.C.
- (D) None of the above
8. To produce cathode spot in a mercury arc rectifier
- (A) Anode is heated
- (B) Tube is evacuated
- (C) An auxiliary electrode is used
- (D) Low mercury vapor pressures are used
9. 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
10. 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