Circuit Breakers MCQs

16. Number of immobile contacts in Double Break Oil Circuit Breaker is:

1. 1
2. 2
3. 3
4. 4

17. During current chopping the current actually breaks

1. During the instant of natural current zero
   
2. Before the instant of natural current zero
   
3. after the instant of natural current zero
   
4. irrespective of the instant of natural zero

18. In which of the following type of relay, the solenoid is used to move in iron core or plunger

1. electrodynamic type
   
2. solenoid type
   
3. induction type
   
4. attracted armature type

19. The rate of rise of restriking voltage is

1. The type of circuit breaker
   
2. The inductance of the system only
   
3. The capacitance of the system only
   
4. The inductance and capacitance of the system only

20. Arcing contacts in a circuit breaker is usually made of

1. Copper tungsten alloy
2. Zinc mercury amalgam
3. Porcelain
4. Graphite