1. What is the primary purpose of a circuit breaker?
(a). Producing abnormal currents
(b). Interrupts abnormal currents and acts as a switch
(c). Maintain abnormal currents
(d). Increase fault currents
2. How can circuit breakers be classified on the basis of current type?
(a). Voltage and current
(b). AC and DC
(c). Low and high
(d). Current and resistance
3. On what basis are AC circuit breakers classified?
(a). Fault currents
(b). Rated voltage
(c). Dielectric properties
(d). Switching speed
4. What are low-voltage AC circuit breakers suitable for?
(a). Voltage less than 5,000 V
(b). Voltage above 10,000 V
(c). Voltage less than 1,000 V
(d). Voltage above 1,000 V
5. What is the classification of high-voltage circuit breakers based on the medium of arc extinction?
(a). Voltage range
(b). Current capacity
(c). Medium of arc extinction
(d). Switching speed
6. What are the main categories of high-voltage circuit breakers?
(a). Oil Circuit Breaker
(b). Air Circuit Breaker
(c). DC circuit breaker
(d). Hybrid Circuit Breaker
7. What is the function of oil in bulk oil circuit breaker?
(a). Conductor of electricity
(b). Insulator for live parts
(c). Arc initiator
(d). Dielectric medium
8. How do low oil content or minimum oil circuit breakers achieve arc extinction?
(a). By the explosive action of oil
(b). By compressed air blast
(c). By sulfur hexafluoride gas
(d). Vacuum disruption
9. What is the appropriate voltage range for circuit breakers with low oil content?
(a). 5 KV to 10 KV
(b). 10 KV to 33 KV
(c). 33 KV to 220 KV
(d). 220 KV to 500 KV
10. How does an oil impulse breaker extinguish the arc?
(a). Oil explosion
(b). Compressed air explosion
(c). The piston pump creates an oil jet
(d). Pressure of sulfur hexafluoride gas
11. What is the main feature of air circuit breaker?
(a). Arc initiation in vacuum
(b). Initiation and extinction of the arc in still air
(c). Arc initiation in oil
(d). Arc initiation in sulfur hexafluoride gas
12. How is the arc extinguished in an air blast circuit breaker?
(a). Oil explosion
(b). Compressed air explosion
(c). Pressure of sulfur hexafluoride gas
(d). Vacuum blockage
13. What is the primary extinguishing medium in sulfur hexafluoride circuit breaker?
(a). Oil
(b). Compressed air
(c). Vacuum
(d). SF6 gas under pressure
14. What is the primary advantage of a vacuum circuit breaker compared to other types?
(a). Oil explosion
(b). Compact size
(c). Compressed air explosion
(d). Pressure of sulfur hexafluoride gas
15. What is the primary disadvantage of oil circuit breaker?
(a). Limited voltage range
(b). High maintenance
(c). Limited breaking capacity
(d). Slow switching speed
16. In what voltage range are air blast circuit breakers generally used?
(a). up to 5 KV
(b). 5 KV to 15 KV
(c). 15 KV to 33 KV
(d). above 33 KV
17. Which property makes sulfur hexafluoride suitable for use in circuit breakers?
(a). Conductivity
(b). Flammability
(c). Dielectric and arc-quenching properties
(d). Corrosivity
18. What is the function of sulfur hexafluoride gas in circuit breakers?
(a). Initiates the arc
(b). Acts as an insulator
(c). Extinguishes the arc
(d). Conducts electricity
19. What is the primary purpose of the piston pump in an oil impulse breaker?
(a). initiates the arc
(b). creates an oil jet to dissipate the arc
(c). compresses air to explode
(d). Generates pressure of sulfur hexafluoride gas.
20. Why are vacuum circuit breakers considered cost effective?
(a). Low maintenance
(b). Use of sulfur hexafluoride gas
(c). Oil spill action
(d). Large size
21. What is the efficient characteristic of vacuum circuit breaker?
(a). Oil explosion
(b). Compact size
(c). Use of dielectric oil
(d). Compressed air explosion
22. What is the primary medium of arc extinction in air circuit breakers?
(a). Vacuum
(b). Sulfur hexafluoride gas
(c). Compressed air
(d). Dielectric oil
23. What is the role of porcelain insulator in low oil content circuit breakers?
(a). Initiates the arc
(b). It involves the explosion of oil.
(c). Conducts electricity
(d). Extinguishes the arc
24. Which circuit breaker type is suitable for medium-high voltage indoor services?
(a). Oil impulse breaker
(b). Air Circuit Breaker
(c). vacuum circuit breaker
(d). Sulfur hexafluoride circuit breaker
25. What makes vacuum circuit breakers long lasting and efficient?
(a). Oil explosion
(b). Compact size
(c). High maintenance
(d). Sealed vacuum interrupter and minimal maintenance