MCQOPTIONS
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MCQOPTIONS
This section includes 104 Mcqs, each offering curated multiple-choice questions to sharpen your Electrical Engineering Questions knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Which of the following medium is employed for extinction of arc in air circuit breaker? |
| A. | Water |
| B. | Oil |
| C. | Air |
| D. | SF6 |
| Answer» D. SF6 | |
| 2. |
Which among these tests are performed to check the nation or international standards? |
| A. | Type test. |
| B. | Production tests. |
| C. | Site checks. |
| D. | All of the above. |
| Answer» B. Production tests. | |
| 3. |
When using air blast circuit breaker, current chopping is a phenomenon observed when |
| A. | A long overhead line is switched off. |
| B. | A bank of capacitors is switched off. |
| C. | A transformer on no load is switched off. |
| D. | A heavy load is switched off. |
| Answer» D. A heavy load is switched off. | |
| 4. |
When a wave propagates on a transmission line, it suffers reflection several times at_____________? |
| A. | tapping |
| B. | load end |
| C. | sending end |
| D. | sending and other end |
| E. | all of the above |
| Answer» E. all of the above | |
| 5. |
When a transmission line is energized, the wave that propagates on it is____________? |
| A. | current wave only |
| B. | voltage wave only |
| C. | Both (A) and (B) |
| D. | power factor wave only |
| Answer» D. power factor wave only | |
| 6. |
Wave trap is used to trap waves of__________________? |
| A. | power frequencies |
| B. | higher frequencies entering generator or transformer units |
| C. | either of the above |
| D. | none of the above |
| Answer» C. either of the above | |
| 7. |
transmission line has reflection coefficient as one? |
| A. | Open circuit |
| B. | Short-circuit |
| C. | Long |
| D. | None of the above |
| Answer» B. Short-circuit | |
| 8. |
To reduce short circuit fault currents are used_____________? |
| A. | reactors |
| B. | resistors |
| C. | capacitors |
| D. | none of the above |
| Answer» B. resistors | |
| 9. |
To protect most of the electrical equipment handling low power, the types of relays used are______________? |
| A. | thermocouple |
| B. | electronic and bimetallic |
| C. | both (A) and (B) |
| D. | none of the above |
| Answer» D. none of the above | |
| 10. |
To limit short-circuit current in a power system are used______________? |
| A. | earth wires |
| B. | isolators |
| C. | H.R.C. fuses |
| D. | reactors |
| Answer» E. | |
| 11. |
Thermal overload relays are used to protect the motor against over current due to____________? |
| A. | short-circuits |
| B. | heavy loads |
| C. | grounds |
| D. | all of the above |
| Answer» C. grounds | |
| 12. |
Thermal circuit breaker has____________? |
| A. | delayed trip action |
| B. | instantaneous trip action |
| C. | both of the above |
| D. | none of the above |
| Answer» B. instantaneous trip action | |
| 13. |
The voltage appearing across the contacts after opening of the circuit breaker is called__________voltage |
| A. | recovery |
| B. | surge |
| C. | operating |
| D. | arc |
| E. | none of the above |
| Answer» B. surge | |
| 14. |
The under voltage relay can be used for______________? |
| A. | generators |
| B. | busbars |
| C. | transformers |
| D. | motors |
| E. | all of the above |
| Answer» F. | |
| 15. |
The torque produced in induction type relay (shaded pole structure) is_____________? |
| A. | inversely proportional to the current |
| B. | inversely proportional to the square of the current |
| C. | proportional to the current |
| D. | proportional to square of the current |
| Answer» C. proportional to the current | |
| 16. |
The time of closing the cycle, in modern circuit breakers is_____________? |
| A. | 0.003 sec |
| B. | 0.001 sec |
| C. | 0.01 sec |
| D. | 0.10 sec |
| E. | none of the above |
| Answer» B. 0.001 sec | |
| 17. |
The steady state stability of the power system can be increased by_____________? |
| A. | connecting lines in parallel |
| B. | connecting lines in series |
| C. | using machines of high impedance |
| D. | reducing the excitation of machines |
| E. | none of the above |
| Answer» B. connecting lines in series | |
| 18. |
The single phasing relays are used for the protection of_____________? |
| A. | single phase motors only |
| B. | two phase motors only |
| C. | two single phase motors running in parallel |
| D. | three phase motors |
| Answer» E. | |
| 19. |
The short circuit in any winding of the transformer is the result of______________? |
| A. | mechanical vibration |
| B. | insulation failure |
| C. | loose connection |
| D. | impulse voltage |
| Answer» E. | |
| 20. |
The short circuit in any winding of the transformer is the result of_______________? |
| A. | mechanical vibration |
| B. | insulation failure |
| C. | loose connection |
| D. | impulse voltage |
| Answer» E. | |
| 21. |
The relay with inverse time characteristic will operate within____________? |
| A. | 1.5 sec |
| B. | 5 to 10 sec |
| C. | 5 to 20 sec |
| D. | 20 to 30 sec |
| E. | none of the above |
| Answer» C. 5 to 20 sec | |
| 22. |
The relay operating speed depends upon_________________? |
| A. | the spring tension |
| B. | the rate of flux built up |
| C. | armature core air gap |
| D. | all of the above |
| Answer» E. | |
| 23. |
The reflection co-efficient at the open circuited end of a transmission line___________? |
| A. | zero |
| B. | infinity |
| C. | unity |
| D. | none of the above |
| Answer» D. none of the above | |
| 24. |
The power loss is an important factor for the design of_______________? |
| A. | transmission line |
| B. | motor |
| C. | generator |
| D. | feeder |
| Answer» B. motor | |
| 25. |
The most efficient torque producing actuating structure for the induction type relays is |
| A. | Shaded pole structure |
| B. | Watt hour meter structure |
| C. | Induction cup structure |
| D. | Single induction loop structure |
| Answer» D. Single induction loop structure | |
| 26. |
The material used for fuse must have_____________? |
| A. | low melting point and high specific resistance |
| B. | low melting point and -low specific resistance |
| C. | high melting point and low specific resistance |
| D. | low melting point and any specific resistance |
| Answer» B. low melting point and -low specific resistance | |
| 27. |
The making and breaking currents of a 3 phase ac circuit breakers in power systems are respectively in ________form. |
| A. | rms value, rms value |
| B. | instantaneous value, rms value |
| C. | rms value, instantaneous value |
| D. | instantaneous value, instantaneous value |
| Answer» E. | |
| 28. |
The main function of a fuse is to_____________? |
| A. | protect the line |
| B. | open the circuit |
| C. | protect the appliance |
| D. | prevent excessive currents |
| E. | none of the above |
| Answer» F. | |
| 29. |
The inverse definite mean time relays are used for over current and earth fault protection of transformer against_________________? |
| A. | heavy loads |
| B. | internal short-circuits |
| C. | external short-circuits |
| D. | all of the above |
| Answer» C. external short-circuits | |
| 30. |
The interrupting time of a circuit breaker is the period between the instant of _________. |
| A. | Initiation of short circuit and the arc extinction on an opening operation |
| B. | Energizing the trip circuit and the arc extension on an opening operation |
| C. | Initiation of short circuit and the parting of primary arc contacts |
| D. | Energizing of the trip circuit and the parting of primary arc contacts |
| Answer» C. Initiation of short circuit and the parting of primary arc contacts | |
| 31. |
The information to the circuit breaker under fault conditions is provided by____________? |
| A. | relay |
| B. | rewirable fuse |
| C. | H.R.C. only |
| D. | all of the above |
| Answer» B. rewirable fuse | |
| 32. |
The inductive interference between power and communication line can be minimized by__________? |
| A. | transposition of the power line |
| B. | transposition of the communication line |
| C. | both (A) and (B) |
| D. | increasing the distance between the conductors |
| Answer» D. increasing the distance between the conductors | |
| 33. |
The heat produced at the contact point owing to flow of electric current is least affected by_____________________. |
| A. | Temperature of the surrounding medium. |
| B. | Contact resistance. |
| C. | Magnitude of electric current flowing. |
| D. | Duration of flow of current. |
| Answer» B. Contact resistance. | |
| 34. |
The ground wire should not be smaller than No _________ copper |
| A. | 2 |
| B. | 4 |
| C. | 6 |
| D. | 10 |
| Answer» E. | |
| 35. |
The fuse wire, in D.C. circuits, is inserted in____________? |
| A. | negative circuit only |
| B. | positive circuit only |
| C. | both (A) and (B) |
| D. | either (A) or (B) |
| Answer» D. either (A) or (B) | |
| 36. |
The fuse rating is expressed in terms of_____________? |
| A. | current |
| B. | voltage |
| C. | VAR |
| D. | kVA |
| Answer» B. voltage | |
| 37. |
The fuse blows off by___________? |
| A. | burning |
| B. | arcing |
| C. | melting |
| D. | none of the above |
| Answer» D. none of the above | |
| 38. |
The delay fuses are used for the protection of ___________? |
| A. | motors |
| B. | power outlet circuits |
| C. | fluorescent lamps |
| D. | light circuits |
| Answer» B. power outlet circuits | |
| 39. |
The current zero interruption, in oil and air blast circuit breakers, is achieved by____________? |
| A. | lengthening of the gap |
| B. | cooling and blast effect |
| C. | both (A) and (B) |
| D. | deionizing the oil with forced air |
| E. | none of the above |
| Answer» D. deionizing the oil with forced air | |
| 40. |
The current zero interruption, in oil and air blast circuit breakers, is achieved by_______________? |
| A. | lengthening of the gap |
| B. | cooling and blast effect |
| C. | both A. and B |
| D. | deionizing the oil with forced air |
| E. | none of the above |
| Answer» D. deionizing the oil with forced air | |
| 41. |
The contacts of high voltage switches used in power system are submerged in oil. The main purpose of the oil is to______________? |
| A. | lubricate the contacts |
| B. | insulate the contacts from switch body |
| C. | extinguish the arc |
| D. | all of the above |
| E. | none of the above |
| Answer» D. all of the above | |
| 42. |
The arcing contacts in a circuit breaker are made of______________? |
| A. | copper tungsten alloy |
| B. | porcelain |
| C. | electrolytic copper |
| D. | aluminium alloy |
| Answer» B. porcelain | |
| 43. |
The arc voltage produced in A.C. circuit breaker is always_____________? |
| A. | in phase with the arc current |
| B. | lagging the arc current by 90″ |
| C. | leading the arc current by 90° |
| D. | none of the above |
| Answer» B. lagging the arc current by 90″ | |
| 44. |
The air blast circuit breakers for 400 kV systems are designed to operate in how much time? |
| A. | 0.1 s |
| B. | 0.5 s |
| C. | 50 ms |
| D. | 100µs |
| Answer» D. 100µs | |
| 45. |
Resistance grounding is used for voltage between_________________? |
| A. | 33kVto66kV |
| B. | HkVto33kV |
| C. | 3.3kVandllkV |
| D. | none of the above |
| Answer» D. none of the above | |
| 46. |
Relays can be designed to respond to changes in________________? |
| A. | resistance, reactance or impedance |
| B. | voltage and current |
| C. | light intensity |
| D. | temperature |
| E. | all above |
| Answer» F. | |
| 47. |
relays are used for phase faults on long line? |
| A. | Impedance |
| B. | Reactance |
| C. | Either of the above |
| D. | None of the above |
| Answer» B. Reactance | |
| 48. |
relay is preferred for phase fault on short transmission line? |
| A. | Induction type |
| B. | Reactance |
| C. | Impedance |
| D. | None of the above |
| Answer» C. Impedance | |
| 49. |
Refer to the following facts to answer the question A 50 Hz, 11 kV, 3 phase alternator with earthed neutral having a reactance of 3 ohms per phase and is connected to a bus bar through a circuit breaker, if the distributed capacitance upto CB between the phase and neutral is 0.01 μ F. What is the frequency of oscillations? |
| A. | 10000 Hz |
| B. | 12500 Hz |
| C. | 12628 Hz |
| D. | 13265 Hz |
| Answer» D. 13265 Hz | |
| 50. |
Refer to the following facts to answer the question, A 50 Hz, 11 kV, 3 phase alternator with earthed neutral having a reactance of 3 ohms per phase and is connected to a bus bar through a circuit breaker, if the distributed capacitance upto CB between the phase and neutral is 0.01 μ F. What is the peak re striking voltage? |
| A. | 18.36 kV |
| B. | 17.96 kV |
| C. | 15.96 kV |
| D. | 12.65 kV |
| Answer» C. 15.96 kV | |