MCQOPTIONS
Saved Bookmarks
MCQOPTIONS
This section includes 86 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. |
The magnitude of the induced e.m.f. in a conductor depends on the______________? |
| A. | flux density of the magnetic field |
| B. | amount of flux cut |
| C. | amount of flux linkages |
| D. | rate of change of flux-linkages |
| Answer» E. | |
| 2. |
The self-inductance of a solenoid is increased when a soft iron core is inserted into it. This is because the soft iron core_______________? |
| A. | Decreases the resistance of the solenoid |
| B. | Reduces the effect of eddy current |
| C. | Improves the flux linkage between the turns of the coil |
| D. | Increases the mutual inductance between the solenoid and the core |
| Answer» D. Increases the mutual inductance between the solenoid and the core | |
| 3. |
The property of coil by which a counter e.m.f. is induced in it when the current through the coil changes is known as__________? |
| A. | self-inductance |
| B. | mutual inductance |
| C. | series aiding inductance |
| D. | capacitance |
| Answer» B. mutual inductance | |
| 4. |
Lagging of changes in the magnetization of a substance behind changes in the magnetic field as the magnetic field is varied is known as magnetic_____________? |
| A. | Retaintivity |
| B. | Permeability |
| C. | Flux |
| D. | Hysteresis |
| Answer» E. | |
| 5. |
Transformer works on the principle of________________? |
| A. | Lenzs law |
| B. | Faradays law |
| C. | Mutual induction |
| D. | Law of conservation of power |
| Answer» D. Law of conservation of power | |
| 6. |
The direction of induced e.m.f. can be found by_____________? |
| A. | Laplace’s law |
| B. | Lenz’s law |
| C. | Fleming’s right hand rule |
| D. | Kirchhoff s voltage law |
| Answer» C. Fleming’s right hand rule | |
| 7. |
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 | |
| 8. |
Self-inductance of a long solenoid is______________? |
| A. | μoN2A |
| B. | μoN2/A |
| C. | μoN2 |
| D. | BA |
| Answer» B. μoN2/A | |
| 9. |
The alternating current has frequency of 106 Hz in such a way that time period for completion of cycle is_______________? |
| A. | 1Hzs |
| B. | 1.5Hzs |
| C. | 106sec |
| D. | 1sec |
| Answer» B. 1.5Hzs | |
| 10. |
For electroplating we use_________________? |
| A. | A D.C source |
| B. | an A.C source |
| C. | any source |
| D. | all of the above |
| Answer» B. an A.C source | |
| 11. |
Self inductance of a coil depends upon________________? |
| A. | current flowing |
| B. | number of turns per unit length |
| C. | voltage produce |
| D. | all |
| Answer» E. | |
| 12. |
If the secondary coil has Ns turns and the primary Np turns the relation between secondary and primary voltages is given by_____________? |
| A. | Vs/Vp = Np/Ns |
| B. | Vs/Vp = Ns/Np |
| C. | Vp/Vs = Ns/Np |
| D. | Vp/Vs = Np/Ns |
| Answer» C. Vp/Vs = Ns/Np | |
| 13. |
Energy stored in a magnetic field is given by______________? |
| A. | LI2 |
| B. | L2I/2 |
| C. | LI2/2 |
| D. | IL2 |
| Answer» D. IL2 | |
| 14. |
The only difference between construction of D.C generator and A.C generator is that of_______________? |
| A. | carbon brushes |
| B. | coil |
| C. | commutator |
| D. | magnetic field |
| Answer» D. magnetic field | |
| 15. |
A laminated iron core has reduced eddy-current losses because____________? |
| A. | more wire can be used with less D.C. resistance in coil |
| B. | the laminations are insulated from each other |
| C. | the magnetic flux is concentrated in the air gap of the core |
| D. | the laminations are stacked vertfcally |
| Answer» C. the magnetic flux is concentrated in the air gap of the core | |
| 16. |
Mutually inductance between two magnetically-coupled coils depends on____________? |
| A. | permeability of the core |
| B. | the number of their turns |
| C. | cross-sectional area of their common core |
| D. | all of the above |
| Answer» E. | |
| 17. |
Which of the following is not a unit of inductance ? |
| A. | Henry |
| B. | Coulomb/volt ampere |
| C. | Volt second per ampere |
| D. | All of the above |
| Answer» C. Volt second per ampere | |
| 18. |
Air-core coils are practically free from______________? |
| A. | hysteresis losses |
| B. | eddy current losses |
| C. | both (A) and (B) |
| D. | none of the above |
| Answer» D. none of the above | |
| 19. |
The law that the induced e.m.f. and current always oppose the cause producing them is due to____________? |
| A. | Faraday |
| B. | Lenz |
| C. | Newton |
| D. | Coulomb |
| Answer» C. Newton | |
| 20. |
If current in a conductor increases then according to Lenz’s law self-induced voltage will____________? |
| A. | aid the increasing current |
| B. | tend to decrease the amount of cur-rent |
| C. | produce current opposite to the in-creasing current |
| D. | aid the applied voltage |
| Answer» D. aid the applied voltage | |
| 21. |
A.C cannot be used for________________? |
| A. | producing heat |
| B. | producing light |
| C. | magnetizing and electroplating |
| D. | all the above |
| Answer» D. all the above | |
| 22. |
Which of the following works on torque on the current carrying conductor placed in magnetic field ? |
| A. | galvanometer |
| B. | ammeter |
| C. | voltmeter |
| D. | all of the above |
| Answer» E. | |
| 23. |
Which one of the following functions like a motor ? |
| A. | galvanometer |
| B. | ammeter |
| C. | voltmeter |
| D. | all of above |
| Answer» E. | |
| 24. |
emf induced in a circuit according to Faradays law depends on the_____________? |
| A. | maximum magnetic flux |
| B. | rate of change of magnetic flux |
| C. | change in magnetic flux |
| D. | initial magnetic flux |
| Answer» C. change in magnetic flux | |
| 25. |
Weber is the unit of_____________? |
| A. | Magnetic field intensity |
| B. | magnetic induction |
| C. | magnetic flux |
| D. | self-inductance |
| Answer» D. self-inductance | |
| 26. |
An alternating current or voltage________________? |
| A. | fluctuates off and on |
| B. | varies in magnitude alone |
| C. | changes its direction again and again |
| D. | changes its magnitude continuously and reverses its direction of flow after regularly recurring intervals |
| Answer» E. | |
| 27. |
A dynamo converts______________? |
| A. | mechanical energy into electrical energy |
| B. | electrical energy into mechanical energy |
| C. | magnetic energy into mechanical energy |
| D. | magnetic energy into electrical energy |
| Answer» B. electrical energy into mechanical energy | |
| 28. |
A.C cannot be used for_______________? |
| A. | producing heat |
| B. | producing light |
| C. | magnetizing and electroplating |
| D. | all the above |
| Answer» D. all the above | |
| 29. |
cmf generated by A.C dynamo depends upon_____________? |
| A. | number of turns in the coil |
| B. | magnetic field strength |
| C. | frequency of rotation |
| D. | all of above |
| Answer» E. | |
| 30. |
The practical illustration of the phenomenon of mutual induction is____________? |
| A. | A.C generator |
| B. | D.C dynamo |
| C. | induction coil |
| D. | transformer |
| Answer» E. | |
| 31. |
The polarity of the induced voltage can be determined by using the left-hand generator rule |
| A. | Yes |
| B. | No |
| Answer» B. No | |
| 32. |
Current produced by moving the loop of wire across a magnetic field is called_____________? |
| A. | A.C current |
| B. | D.C current |
| C. | induced current |
| D. | mean square current |
| Answer» D. mean square current | |
| 33. |
Reversing the field or the current will reverse the force on the conductor |
| A. | Yes |
| B. | No |
| Answer» B. No | |
| 34. |
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. | Yes |
| B. | No |
| Answer» C. | |
| 35. |
A crack in the magnetic path of an inductor will result in________________? |
| A. | unchanged inductance |
| B. | increased inductance |
| C. | zero inductance |
| D. | reduced inductance |
| Answer» E. | |
| 36. |
Which circuit element(s) will oppose the change in circuit current ? |
| A. | Resistance only |
| B. | Inductance only |
| C. | Capacitance only |
| D. | Inductance and capacitance |
| Answer» C. Capacitance only | |
| 37. |
The co-efficient of coupling between two air core coils depends on____________? |
| A. | self-inductance of two coils only |
| B. | mutual inductance between two coils only |
| C. | mutual inductance and self inductance of two coils |
| D. | none of the above |
| Answer» D. none of the above | |
| 38. |
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 | |
| 39. |
A.C can not be used for_______________? |
| A. | producing heat |
| B. | producing light |
| C. | Magnetizing iron |
| D. | Producing magnetic field |
| Answer» D. Producing magnetic field | |
| 40. |
Magnetic compass needle will be deflecting if it is kept near________________? |
| A. | Static charge |
| B. | Soft iron |
| C. | Semi-conductor |
| D. | Accelerating charge |
| Answer» E. | |
| 41. |
The emf induced in a coil by a changing magnetic flux may have unit as______________? |
| A. | ms-1A |
| B. | ms-2A-1 |
| C. | kgms2A-1 |
| D. | kgm2s-1A-1 |
| Answer» E. | |
| 42. |
A small coil lies inside a large coil. The two coils are horizontal concentric and carry currents in opposite directions. The large coil will experience______________? |
| A. | A torque about horizontal axis |
| B. | A torque about vertical axis |
| C. | An upward force along the axis |
| D. | No resultant force |
| Answer» E. | |
| 43. |
The emf induced in a conductor of unit length moving with unit velocity at right angles to a magnetic field is equal to_____________? |
| A. | Magnetic flux density |
| B. | Torque |
| C. | Mutual induction |
| D. | Motional emf |
| Answer» B. Torque | |
| 44. |
Power loss in actual transformer is due to_________________? |
| A. | Small output |
| B. | Eddy currents and magnetic hysterias |
| C. | Soft iron core |
| D. | Back emf |
| Answer» C. Soft iron core | |
| 45. |
A.C and D.C have the same______________? |
| A. | effect in charging a capacitor |
| B. | effect in charging a battery |
| C. | effect while passing through an inductance |
| D. | heating effect through a resistance |
| Answer» E. | |
| 46. |
Which of the following uses electric energy and does not convert it into any other form ? |
| A. | transformer |
| B. | motor |
| C. | D.C generator |
| D. | A.C generator |
| Answer» B. motor | |
| 47. |
An aeroplane of wingspan 10m flies from the equator towards the North Pole. The wings are perpendicular to the vertical component of the earths magnetic field (B = 4×10-5T). At maximum speed an emf of 96mV is induced across the wing tips. The maximum speed of the aeroplane is____________? |
| A. | 150msec-1 |
| B. | 384msec-1 |
| C. | 38.4msec-1 |
| D. | 200msec-1 |
| Answer» C. 38.4msec-1 | |
| 48. |
Inductors acts as a short circuit for_______________? |
| A. | AC |
| B. | DC |
| C. | Both A and B |
| D. | none of these |
| Answer» C. Both A and B | |
| 49. |
Non inductive resistances are used in decreasing______________? |
| A. | Mutual inductance |
| B. | Self inductance |
| C. | Magnetic fields |
| D. | Heating effect |
| Answer» C. Magnetic fields | |
| 50. |
If the coil is wound on an iron core the flux through it will_______________? |
| A. | decrease |
| B. | become zero |
| C. | remain the same |
| D. | increase |
| Answer» E. | |