A. 25°C
B. 40°C
C. 60°C
D. 75°C
Related Mcqs:
- Ageing of a selenium rectifier may change the output voltage by__________?
A. 5 to 10 per cent
B. 15 to 20 per cent
C. 25 to 30 per cent
D. none of the above - In selenium rectifiers efficiencies ranging from _______ to _______ percent are attainable?
A. 25, 35
B. 40, 50
C. 60, 70
D. 75, 85 - 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 - A commutating rectifier consists of commutator driven by___________?
A. an induction motor
B. a synchronous motor
C. a D.C. series motor
D. a D.C. shunt motor - 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 - The efficiency of an electrolytic rectifier is nearly____________?
A. 80%
B. 70%
C. 60%
D. 40% - If cathode and anode connections in a mercury arc rectifier are inter changed_____________?
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 - In a mercury pool rectifier, the voltage drop across its electrodes___________?
A. is directly proportional to load
B. is inversely proportional to load
C. varies exponentially with the load current
D. is almost independent of load current - 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 - In a mercury arc rectifier positive ions are attracted towards______________?
A. anode
B. cathode
C. shell bottom
D. mercury pool
