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. |
Conductivity is analogous to |
| A. | etentivity |
| B. | esistivity |
| C. | ermeability |
| D. | nductance |
| Answer» D. nductance | |
| 2. |
The property of a material which opposes the creation of magnetic flux in it is known as |
| A. | eluctivity |
| B. | agneto-motive force |
| C. | ermeance |
| D. | eluctance |
| Answer» E. | |
| 3. |
The rate of rise of current through an inductive coil is maximum |
| A. | t 63.2% of its maximum steady value |
| B. | t the start of the current flow |
| C. | fter one time constant |
| D. | ear the final maximum value of current |
| Answer» C. fter one time constant | |
| 4. |
Hysteresis loss least depends on |
| A. | olume of material |
| B. | requency |
| C. | teinmetz’s coefficient of material |
| D. | mbient temperature |
| Answer» E. | |
| 5. |
The unit of reluctance is |
| A. | eter/Henry |
| B. | enry/meter |
| C. | enry |
| D. | /Henry |
| Answer» E. | |
| 6. |
Hard steel is suitable for making permanent magnets because |
| A. | t has good residual magnetism |
| B. | ts hysteresis loop has large area |
| C. | ts mechanical strength is high |
| D. | ts mechanical strength is low |
| Answer» B. ts hysteresis loop has large area | |
| 7. |
Reciprocal of reluctance is |
| A. | eluctivity |
| B. | ermeance |
| C. | ermeability |
| D. | usceptibility |
| Answer» C. ermeability | |
| 8. |
A material for good magnetic memory should have |
| A. | ow hysteresis loss |
| B. | igh permeability |
| C. | ow retentivity |
| D. | igh retentivity |
| Answer» E. | |
| 9. |
Permanent magnets are normally made of |
| A. | lnico alloys |
| B. | luminium |
| C. | ast iron |
| D. | rought iron |
| Answer» B. luminium | |
| 10. |
Conductance is analogous to |
| A. | ermeance |
| B. | eluctance |
| C. | lux |
| D. | nductance |
| Answer» B. eluctance | |
| 11. |
An air gap is usually inserted in magnetic circuits to |
| A. | ncrease m.m.f. |
| B. | ncrease the flux |
| C. | revent saturation |
| D. | one of the above |
| Answer» D. one of the above | |
| 12. |
The unit of retentivity is |
| A. | eber |
| B. | eber/sq. m |
| C. | mpere turn/meter |
| D. | mpere turns |
| Answer» C. mpere turn/meter | |
| 13. |
Silicon steel is used in electrical machines because it has |
| A. | ow coercivity |
| B. | ow retentivity |
| C. | ow hysteresis loss |
| D. | igh coercivity |
| Answer» D. igh coercivity | |
| 14. |
In a magnetic material hysteresis loss takes place primarily due to |
| A. | apid reversals of its magnetization |
| B. | lux density lagging behind magnetizing force |
| C. | olecular friction |
| D. | t high retentivity |
| Answer» E. | |
| 15. |
The initial rate of rise of current through a coil of inductance 10 H when suddenly connected to a D.C. supply of 200 V is ___________Vs |
| A. | 0 |
| B. | 0 |
| C. | 0.05 |
| D. | 00 |
| Answer» C. 0.05 | |
| 16. |
Laminated cores, in electrical machines, are used to reduce |
| A. | opper loss |
| B. | ddy current loss |
| C. | ysteresis loss |
| D. | ll of the above |
| Answer» C. ysteresis loss | |
| 17. |
Energy stored by a coil is doubled when its current is increased by percent. |
| A. | 25 |
| B. | 50.14 |
| C. | 41.4 |
| D. | 100 |
| Answer» D. 100 | |
| 18. |
If the area of hysteresis loop of a material is large, the hysteresis loss in this material will be |
| A. | Zero |
| B. | Small |
| C. | Large |
| D. | None of the above |
| Answer» D. None of the above | |
| 19. |
Permeability in a magnetic circuit corresponds to_________ in an electric circuit. |
| A. | Resistance |
| B. | Resistivity |
| C. | Conductivity |
| D. | Conductance |
| Answer» D. Conductance | |
| 20. |
Those materials are well suited for making permanent magnets which have ________ retentivity and ________ coercivity. |
| A. | Low, high |
| B. | High, high |
| C. | High, low |
| D. | Low, low |
| Answer» C. High, low | |
| 21. |
Point out the wrong statement. Magnetic leakage is undesirable in electric machines because it |
| A. | Lowers their power efficiency |
| B. | Increases their cost of manufacture |
| C. | Leads to their increased weight |
| D. | Produces fringing |
| Answer» B. Increases their cost of manufacture | |
| 22. |
Conductivity is analogous to%! |
| A. | Retentivity |
| B. | Resistivity |
| C. | Permeability |
| D. | Inductance |
| Answer» D. Inductance | |
| 23. |
The property of a material which opposes the creation of magnetic flux in it is known as%! |
| A. | Reluctivity |
| B. | Magneto-motive force |
| C. | Permeance |
| D. | Reluctance |
| Answer» E. | |
| 24. |
The rate of rise of current through an inductive coil is maximum%! |
| A. | At 63.2% of its maximum steady value |
| B. | At the start of the current flow |
| C. | After one time constant |
| D. | Near the final maximum value of current |
| Answer» C. After one time constant | |
| 25. |
Permeability in a magnetic circuit corresponds to_________ in an electric circuit.%! |
| A. | Resistance |
| B. | Resistivity |
| C. | Conductivity |
| D. | Conductance |
| Answer» D. Conductance | |
| 26. |
Reciprocal of reluctance is%! |
| A. | Reluctivity |
| B. | Permeance |
| C. | Permeability |
| D. | Susceptibility |
| Answer» C. Permeability | |
| 27. |
An air gap is usually inserted in magnetic circuits to%! |
| A. | Increase m.m.f. |
| B. | Increase the flux |
| C. | Prevent saturation |
| D. | None of the above |
| Answer» D. None of the above | |
| 28. |
Those materials are well suited for making permanent magnets which have ________ retentivity and ________ coercivity.%! |
| A. | Low, high |
| B. | High, high |
| C. | High, low |
| D. | Low, low |
| Answer» C. High, low | |
| 29. |
*$_Reciprocal of reluctance is? |
| A. | Reluctivity |
| B. | Permeance |
| C. | Permeability |
| D. | Susceptibility |
| Answer» C. Permeability | |
| 30. |
*$_An air gap is usually inserted in magnetic circuits to? |
| A. | Increase m.m.f. |
| B. | Increase the flux |
| C. | Prevent saturation |
| D. | None of the above |
| Answer» D. None of the above | |
| 31. |
*$_Permeability in a magnetic circuit corresponds to_________ in an electric circuit.? |
| A. | Resistance |
| B. | Resistivity |
| C. | Conductivity |
| D. | Conductance |
| Answer» D. Conductance | |
| 32. |
*$_Those materials are well suited for making permanent magnets which have ________ retentivity and ________ coercivity.? |
| A. | Low, high |
| B. | High, high |
| C. | High, low |
| D. | Low, low |
| Answer» C. High, low | |
| 33. |
*/*_In a magnetic material hysteresis loss takes place primarily due to? |
| A. | Rapid reversals of its magnetization |
| B. | Flux density lagging behind magnetizing force |
| C. | Molecular friction |
| D. | It high retentivity |
| Answer» E. | |
| 34. |
*/*_A material for good magnetic memory should have? |
| A. | Low hysteresis loss |
| B. | High permeability |
| C. | Low retentivity |
| D. | High retentivity |
| Answer» E. | |
| 35. |
*/*_The unit of retentivity is? |
| A. | Weber |
| B. | Weber/sq. m |
| C. | Ampere turn/meter |
| D. | Ampere turns |
| Answer» C. Ampere turn/meter | |
| 36. |
*/*_Laminated cores, in electrical machines, are used to reduce? |
| A. | Copper loss |
| B. | Eddy current loss |
| C. | Hysteresis loss |
| D. | All of the above |
| Answer» C. Hysteresis loss | |
| 37. |
%_A material for good magnetic memory should have_% |
| A. | Low hysteresis loss |
| B. | High permeability |
| C. | Low retentivity |
| D. | High retentivity |
| Answer» E. | |
| 38. |
%_The unit of retentivity is_% |
| A. | Weber |
| B. | Weber/sq. m |
| C. | Ampere turn/meter |
| D. | Ampere turns |
| Answer» C. Ampere turn/meter | |
| 39. |
%_In a magnetic material hysteresis loss takes place primarily due to_% |
| A. | Rapid reversals of its magnetization |
| B. | Flux density lagging behind magnetizing force |
| C. | Molecular friction |
| D. | It high retentivity |
| Answer» E. | |
| 40. |
_ Laminated cores, in electrical machines, are used to reduce$? |
| A. | Copper loss |
| B. | Eddy current loss |
| C. | Hysteresis loss |
| D. | All of the above |
| Answer» C. Hysteresis loss | |
| 41. |
_Permanent magnets are normally made of$? |
| A. | Alnico alloys |
| B. | Aluminium |
| C. | Cast iron |
| D. | Wrought iron |
| Answer» B. Aluminium | |
| 42. |
_If the area of hysteresis loop of a material is large, the hysteresis loss in this material will be$? |
| A. | Zero |
| B. | Small |
| C. | Large |
| D. | None of the above |
| Answer» D. None of the above | |
| 43. |
_Relative permeability of vacuum is$? |
| A. | 1 |
| B. | 1 H/m |
| C. | 1/4JI |
| D. | 4n √ó 10' H/m |
| Answer» B. 1 H/m | |
| 44. |
_The unit of magnetic flux is$? |
| A. | Henry |
| B. | Weber |
| C. | Ampere-turn/weber |
| D. | Ampere/metre |
| Answer» C. Ampere-turn/weber | |
| 45. |
The initial rate of rise of current through a coil of inductance 10 H when suddenly connected to a D.C. supply of 200 V is ___________Vs$? |
| A. | 50 |
| B. | 20 |
| C. | 0.05 |
| D. | 500 |
| Answer» C. 0.05 | |
| 46. |
Conductance is analogous to$? |
| A. | Permeance |
| B. | Reluctance |
| C. | Flux |
| D. | Inductance |
| Answer» B. Reluctance | |
| 47. |
Silicon steel is used in electrical machines because it has$? |
| A. | Low coercivity |
| B. | Low retentivity |
| C. | Low hysteresis loss |
| D. | High coercivity |
| Answer» D. High coercivity | |
| 48. |
Point out the wrong statement. Magnetic leakage is undesirable in electric machines because it$? |
| A. | Lowers their power efficiency |
| B. | Increases their cost of manufacture |
| C. | Leads to their increased weight |
| D. | Produces fringing |
| Answer» B. Increases their cost of manufacture | |
| 49. |
Conductance is analogous to? |
| A. | Permeance |
| B. | Reluctance |
| C. | Flux |
| D. | Inductance |
| Answer» B. Reluctance | |
| 50. |
Silicon steel is used in electrical machines because it has? |
| A. | Low coercivity |
| B. | Low retentivity |
| C. | Low hysteresis loss |
| D. | High coercivity |
| Answer» D. High coercivity | |