MCQOPTIONS
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MCQOPTIONS
This section includes 56 Mcqs, each offering curated multiple-choice questions to sharpen your Electrical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
A coil of wire is arranged with its plane perpendicular to a uniform magnetic field o flux density B. when the radius of the coil increases from r1 to r2 in time Δt then what is the emf induced in the coil ? |
| A. | ωB/r22-r12/Δt |
| B. | ωB(r2-r1)2/Δt |
| C. | ωB(r22-r12)/Δt |
| D. | ωB(r22+r12)/Δt |
| Answer» D. ωB(r22+r12)/Δt | |
| 2. |
A coil with negligible resistance has 50V across it with 10 mA. The inductive reactance is_____________? |
| A. | 50 ohms |
| B. | 500 ohms |
| C. | 1000 ohms |
| D. | 5000 ohms |
| Answer» E. | |
| 3. |
A coil is wound on iron core which carries current I. The self-induced voltage in the coil is not affected by________________? |
| A. | variation in coil current |
| B. | variation in voltage to the coil |
| C. | change of number of turns of coil |
| D. | the resistance of magnetic path |
| Answer» C. change of number of turns of coil | |
| 4. |
A coil induces 350 mV when the current changes at the rate of 1 A/s. The value of inductance is___________? |
| A. | 3500 mH |
| B. | 350 mH |
| C. | 250 mH |
| D. | 150 mH |
| Answer» C. 250 mH | |
| 5. |
A 500 turns solenoid develops an average induced voltage of 60 V. Over what time interval must a flux change of 0.06 Wb occur to produce such a voltage ? |
| A. | 0.01 s |
| B. | 0.1 s |
| C. | 0.5 s |
| D. | 5 s |
| Answer» D. 5 s | |
| 6. |
A 200 turn coil has an inductance of 12 mH. If the number of turns is increased to 400 turns, all other quantities (area, length etc.) remaining the same, the inductance will be___________? |
| A. | 6 mH |
| B. | 14 mH |
| C. | 24 mH |
| D. | 48 mH |
| Answer» E. | |
| 7. |
The magnitude of the induced e.m.f. in a conductor depends on the |
| A. | lux density of the magnetic field |
| B. | mount of flux cut |
| C. | mount of flux linkages |
| D. | ate of change of flux-linkages |
| Answer» E. | |
| 8. |
The law that the induced e.m.f. and current always oppose the cause producing them is due to |
| A. | araday |
| B. | enz |
| C. | ewton |
| D. | oulomb |
| Answer» C. ewton | |
| 9. |
An average voltage of 10 V is induced in a 250 turns solenoid as a result of a change in flux which occurs in 0.5 second. The total flux change is |
| A. | 0 Wb |
| B. | Wb |
| C. | .2 Wb |
| D. | .02 Wb |
| Answer» E. | |
| 10. |
In case of an inductance, current is proportional to |
| A. | oltage across the inductance |
| B. | agnetic field |
| C. | oth A and B |
| D. | either A)nor B |
| Answer» C. oth A and B | |
| 11. |
Higher the self-inductance of a coil, |
| A. | esser its weber-turns |
| B. | ower the e.m.f. induced |
| C. | reater the flux produced by it |
| D. | onger the delay in establishing steady current through it |
| Answer» E. | |
| 12. |
In an iron cored coil the iron core is removed so that the coil becomes an air cored coil. The inductance of the coil will |
| A. | ncrease |
| B. | ecrease |
| C. | emain the same |
| D. | nitially increase and then decrease |
| Answer» C. emain the same | |
| 13. |
The direction of induced e.m.f. can be found by |
| A. | aplace's law |
| B. | enz's law |
| C. | leming's right hand rule |
| D. | irchhoff s voltage law |
| Answer» C. leming's right hand rule | |
| 14. |
A coil induces 350 mV when the current changes at the rate of 1 A/s. The value of inductance is |
| A. | 500 mH |
| B. | 50 mH |
| C. | 50 mH |
| D. | 50 mH |
| Answer» C. 50 mH | |
| 15. |
Air-core coils are practically free from |
| A. | ysteresis losses |
| B. | ddy current losses |
| C. | oth A and B |
| D. | one of the above |
| Answer» D. one of the above | |
| 16. |
The coefficient of coupling between two air core coils depends on |
| A. | elf-inductance of two coils only |
| B. | utual inductance between two coils only |
| C. | utual inductance and self inductance of two coils |
| D. | one of the above |
| Answer» D. one of the above | |
| 17. |
As per Faraday's laws of electromagnetic induction, an e.m.f. is induced in a conductor whenever it |
| A. | ies perpendicular to the magnetic flux |
| B. | ies in a magnetic field |
| C. | uts magnetic flux |
| D. | oves parallel to the direction of the magnetic field |
| Answer» D. oves parallel to the direction of the magnetic field | |
| 18. |
The self-inductance of the coil may be defined as equal to the e.m.f. induced in volts when the current in the circuit changes at the rate of unit Weber turns. |
| A. | es |
| B. | o |
| Answer» C. | |
| 19. |
The inductance of a coil will increase under all the following conditions except |
| A. | hen more length for the same number of turns is provided |
| B. | hen the number of turns of the coil increase |
| C. | hen more area for each turn is provided |
| D. | hen permeability of the core increases |
| Answer» B. hen the number of turns of the coil increase | |
| 20. |
Which of the following circuit element stores energy in the electromagnetic field? |
| A. | nductance |
| B. | ondenser |
| C. | ariable resistor |
| D. | esistance |
| Answer» B. ondenser | |
| 21. |
An e.m.f. of 16 volts is induced in a coil of inductance 4H. The rate of change of current must be |
| A. | 4 A/s |
| B. | 2 A/s |
| C. | 6 A/s |
| D. | A/s |
| Answer» E. | |
| 22. |
A 200 turn coil has an inductance of 12 mH. If the number of turns is increased to 400 turns, all other quantities (area, length etc.) remaining the same, the inductance will be |
| A. | mH |
| B. | 46 mH |
| C. | 4 mH |
| D. | 8 mH |
| Answer» E. | |
| 23. |
The core of a coil has a length of 200 mm. The inductance of coil is 6 mH. If the core length is doubled, all other quantities, remaining the same, the inductance will be |
| A. | mH |
| B. | 2 mH |
| C. | 4 mH |
| D. | 8 mH |
| Answer» B. 2 mH | |
| 24. |
A conductor 2 meters long moves at right angles to a magnetic field of flux density 1 tesla with a velocity of 12.5 m/s. The induced e.m.f. in the conductor will be |
| A. | 0 V |
| B. | 5 V |
| C. | 5 V |
| D. | 0 V |
| Answer» D. 0 V | |
| 25. |
The polarity of the induced voltage can be determined by using the left-hand generator rule. |
| A. | es |
| B. | o |
| Answer» B. o | |
| 26. |
Both the number of turns and the core length of an inductive coil are doubled. Its self-inductance will be |
| A. | naffected |
| B. | oubled |
| C. | alved |
| D. | uadrupled |
| Answer» C. alved | |
| 27. |
Find the force acting on a conductor 3m long carrying a current of 50 amperes at right angles to a magnetic field having a flux density of 0.67 tesla |
| A. | 00 N |
| B. | 00 N |
| C. | 00 N |
| D. | 000 N |
| Answer» B. 00 N | |
| 28. |
Which of the following inductor will have the least eddy current losses? |
| A. | ir core |
| B. | aminated iron core |
| C. | ron core |
| D. | owdered iron core |
| Answer» B. aminated iron core | |
| 29. |
Mutually inductance between two magnetically coupled coils depends on |
| A. | ermeability of the core |
| B. | he number of their turns |
| C. | ross-sectional area of their common core |
| D. | ll of the above |
| Answer» E. | |
| 30. |
A coil is wound on iron core which carries current I. The self-induced voltage in the coil is not affected by |
| A. | ariation in coil current |
| B. | ariation in voltage to the coil |
| C. | hange of number of turns of coil |
| D. | he resistance of magnetic path |
| Answer» C. hange of number of turns of coil | |
| 31. |
Two coils have self-inductances of 10 H and 2 H, the mutual inductance being zero. If the two coils are connected in series, the total inductance will be |
| A. | H |
| B. | H |
| C. | 2 H |
| D. | 4 H |
| Answer» D. 4 H | |
| 32. |
Two coils have inductances of 8 mH and 18 mH and a coefficient of coupling of 0.5. If the two coils are connected in series aiding, the total inductance will be |
| A. | 2 mH |
| B. | 8 mH |
| C. | 0 mH |
| D. | 8 mH |
| Answer» C. 0 mH | |
| 33. |
Reversing the field or the current will reverse the force on the conductor. |
| A. | es |
| B. | o |
| Answer» B. o | |
| 34. |
The self inductances of two coils are 8 mH and 18 mH. If the coefficient of coupling is 0.5, the mutual inductance of the coils is |
| A. | mH |
| B. | mH |
| C. | mH |
| D. | 2 mH |
| Answer» D. 2 mH | |
| 35. |
Which of the following is unit of inductance? |
| A. | hm |
| B. | enry |
| C. | mpere turns |
| D. | eber/metre |
| Answer» C. mpere turns | |
| 36. |
Which of the following is not a unit of inductance? |
| A. | enry |
| B. | oulomb/volt ampere |
| C. | olt second per ampere |
| D. | ll of the above |
| Answer» C. olt second per ampere | |
| 37. |
A coil with negligible resistance has 50V across it with 10 mA. The inductive reactance is |
| A. | 0 ohms |
| B. | 00 ohms |
| C. | 000 ohms |
| D. | 000 ohms |
| Answer» E. | |
| 38. |
A 500 turns solenoid develops an average induced voltage of 60 V. Over what time interval must a flux change of 0.06 Wb occur to produce such a voltage? |
| A. | .01 s |
| B. | .1 s |
| C. | .5 s |
| Answer» D. | |
| 39. |
Which of the fpllowing inductor will have the least eddy current losses ? |
| A. | ir core |
| B. | aminated iron core |
| C. | ron core |
| D. | owdered iron core |
| Answer» B. aminated iron core | |
| 40. |
A moving magnetic field will produce the same effect as a conductor that is moving. |
| A. | rue |
| B. | alse |
| Answer» B. alse | |
| 41. |
Increasing the field or increasing the current will decrease the force on the conductor. |
| A. | es |
| B. | o |
| Answer» C. | |
| 42. |
A crack in the magnetic path of an inductor will result in |
| A. | nchanged inductance |
| B. | ncreased inductance |
| C. | ero inductance |
| D. | educed inductance |
| Answer» E. | |
| 43. |
A conductor carries 125 amperes of current under 60° to a magnetic field of 1.1 tesla. The force on the conductor will be nearly |
| A. | 0 N |
| B. | 20 N |
| C. | 40 N |
| D. | 80 N |
| Answer» C. 40 N | |
| 44. |
Two 300 uH coils in series without mutual coupling have a total inductance of |
| A. | 00 uH |
| B. | 00 uH |
| C. | 50 uH |
| D. | 5 uH |
| Answer» C. 50 uH | |
| 45. |
In case all the flux from the current in coil 1 links with coil 2, the coefficient of coupling will be |
| A. | 0 |
| B. | 0 |
| C. | 0.5 |
| D. | ero |
| Answer» C. 0.5 | |
| 46. |
Which of the following circuit elements will oppose the change in circuit current? |
| A. | apacitance |
| B. | nductance |
| C. | esistance |
| D. | ll of the above |
| Answer» C. esistance | |
| 47. |
WHAT_IS_EMF??$ |
| A. | Force |
| B. | Voltage |
| C. | Current |
| D. | Flux |
| Answer» C. Current | |
| 48. |
WHAT_DOES_EMF_STAND_FOR??$ |
| A. | Electronic magnetic force |
| B. | Electromotive force |
| C. | Electromagnetic force |
| D. | Electromated force |
| Answer» C. Electromagnetic force | |
| 49. |
Find the strength of the magnetic field in a conductor 0.5m long moving with a velocity of 10m/s, inducing an emf of 20V? |
| A. | 1T |
| B. | 2T |
| C. | 3T |
| D. | 4T |
| Answer» E. | |
| 50. |
Find the length of a conductor which is moving with a velocity 0.4m/s in a magnetic field of 8T, inducing an emf of 20V. |
| A. | 50m |
| B. | 5m |
| C. | 6.25m |
| D. | 0.5m |
| Answer» D. 0.5m | |