MCQOPTIONS
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MCQOPTIONS
This section includes 95 Mcqs, each offering curated multiple-choice questions to sharpen your Electrical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 51. |
_Main causes of noisy solenoid are$? |
| A. | strong tendency of fan out of laminations at the end caused by repulsion among magnetic lines of force |
| B. | uneven bearing surface, caused by dirt or uneven wear between moving and stationary parts |
| C. | both of above |
| D. | none of the above |
| Answer» D. none of the above | |
| 52. |
_The magnetic reluctance of a material$? |
| A. | decreases with increasing cross sectional area of material |
| B. | increases with increasing cross-sec-tional area of material |
| C. | does not vary with increasing cross-sectional area of material |
| D. | any of the above |
| Answer» B. increases with increasing cross-sec-tional area of material | |
| 53. |
_Paramagnetic materials have relative permeability$? |
| A. | slightly less than unity |
| B. | equal to unity |
| C. | slightly more than unity |
| D. | equal to that ferromagnetic mate rials |
| Answer» D. equal to that ferromagnetic mate rials | |
| 54. |
_A permanent magnet$? |
| A. | attracts some substances and repels others |
| B. | attracts all paramagnetic substances and repels others |
| C. | attracts only ferromagnetic substances |
| D. | attracts ferromagnetic substances and repels all others |
| Answer» B. attracts all paramagnetic substances and repels others | |
| 55. |
_The relative permeability of materials is not constant.$? |
| A. | diamagnetic |
| B. | paramagnetic |
| C. | ferromagnetic |
| D. | insulating |
| Answer» D. insulating | |
| 56. |
_When an iron piece is placed in a magnetic field$? |
| A. | the magnetic lines of force will bend away from their usual paths in order to go away from the piece |
| B. | the magnetic lines of force will bend away from their usual paths in order to pass through the piece |
| C. | the magnetic field will not be affected |
| D. | the iron piece will break |
| Answer» C. the magnetic field will not be affected | |
| 57. |
_The materials having low retentivity are suitable for making$? |
| A. | weak magnets |
| B. | temporary magnets |
| C. | permanent magnets |
| D. | none of the above |
| Answer» C. permanent magnets | |
| 58. |
The commonly used material for shielding or screening magnetism is$? |
| A. | copper |
| B. | aluminium |
| C. | soft iron |
| D. | brass |
| Answer» D. brass | |
| 59. |
Magnetism of a magnet can be destroyed by$? |
| A. | heating |
| B. | hammering |
| C. | by inductive action of another magnet |
| D. | by all above methods |
| Answer» E. | |
| 60. |
Fleming's left hand rule is used to find$? |
| A. | Direction of magnetic field due to current carrying conductor |
| B. | Direction of flux in a solenoid |
| C. | Direction of force on a current carrying conductor in a magnetic field |
| D. | Polarity of a magnetic pole |
| Answer» D. Polarity of a magnetic pole | |
| 61. |
The bar magnet has$? |
| A. | the dipole moment |
| B. | monopole moment |
| C. | (A) and (B) both |
| D. | none of the above |
| Answer» B. monopole moment | |
| 62. |
The working of a meter is based on the use of a permanent magnet. In order to protect the meter functioning from stray magnetic fields$? |
| A. | meter is surrounded by strong magnetic fields |
| B. | a soft iron shielding is used |
| C. | a plastic shielding is provided |
| D. | a shielding of anon-magnetic material is used |
| Answer» C. a plastic shielding is provided | |
| 63. |
The working of a meter is based on the use of a permanent magnet. In order to protect the meter functioning from stray magnetic fields? |
| A. | meter is surrounded by strong magnetic fields |
| B. | a soft iron shielding is used |
| C. | a plastic shielding is provided |
| D. | a shielding of anon-magnetic material is used |
| Answer» C. a plastic shielding is provided | |
| 64. |
Fleming's left hand rule is used to find? |
| A. | Direction of magnetic field due to current carrying conductor |
| B. | Direction of flux in a solenoid |
| C. | Direction of force on a current carrying conductor in a magnetic field |
| D. | Polarity of a magnetic pole |
| Answer» D. Polarity of a magnetic pole | |
| 65. |
The bar magnet has? |
| A. | the dipole moment |
| B. | monopole moment |
| C. | (A) and (B) both |
| D. | none of the above |
| Answer» B. monopole moment | |
| 66. |
Degaussing is the process of? |
| A. | removal of magnetic impurities |
| B. | removing gases from the materials |
| C. | remagnetising metallic parts |
| D. | demagnetising metallic parts |
| Answer» E. | |
| 67. |
Which of the following materials are diamagnetic?? |
| A. | Silver |
| B. | Copper |
| C. | Silver and copper |
| D. | Iron |
| Answer» D. Iron | |
| 68. |
A certain amount of current flows through a ring shaped coil with fixed number of turns. How does the magnetic induction B varies inside the coil if an iron core is threaded into coil without dimensional change of coil?? |
| A. | Decreases |
| B. | Increases |
| C. | Remains same |
| D. | First increases and then decreases depending on the depth of iron in¬sertion |
| Answer» C. Remains same | |
| 69. |
Indicate which of the following material does not retain magnetism permanently.? |
| A. | Soft iron |
| B. | Stainless steel |
| C. | Hardened steel |
| D. | None of the above |
| Answer» B. Stainless steel | |
| 70. |
A material which is slightly repelled by a magnetic field is known as? |
| A. | ferromagnetic material |
| B. | diamagnetic material |
| C. | paramagnetic material |
| D. | conducting material |
| Answer» C. paramagnetic material | |
| 71. |
In the left hand rule, forefinger always represents? |
| A. | voltage |
| B. | current |
| C. | magnetic field |
| D. | direction of force on the conductor |
| Answer» D. direction of force on the conductor | |
| 72. |
A rectangular magnet of magnetic moment M is cut into two piece of same length, the magnetic moment of each piece will be? |
| A. | M |
| B. | M/2 |
| C. | 2 M |
| D. | M/4 |
| Answer» C. 2 M | |
| 73. |
Two long parallel conductors carry 100 A. If the conductors are separated by 20 mm, the force per meter of length of each conductor will be? |
| A. | 100 N |
| B. | 10 N |
| C. | 1 N |
| D. | 0.1 N |
| Answer» E. | |
| 74. |
A square cross-sectional magnet has a pole strength of 1 x 10 Wb and cross sectional area of 20 mm x 20 mm. What is the strength at a distance of 100 mm from the unit pole in air ?? |
| A. | 63.38 N/Wb |
| B. | 633.8 N/Wb |
| C. | 6338 N/Wb |
| D. | 63380 N/Wb |
| Answer» D. 63380 N/Wb | |
| 75. |
A keeper is used to? |
| A. | change the direction of magnetic lines |
| B. | amplify flux |
| C. | restore lost flux |
| D. | provide a closed path for flux |
| Answer» E. | |
| 76. |
Hysteresis loop in case of magnetically hard materials is more in shape as compared to magnetically soft materials.? |
| A. | circular |
| B. | triangular |
| C. | rectangular |
| D. | none of the above |
| Answer» D. none of the above | |
| 77. |
What will be the magnetic potential difference across the air gap of 2 cm length in magnetic field of 200 AT/m?? |
| A. | 2 AT |
| B. | 4 AT |
| C. | 6 AT |
| D. | 10 AT |
| Answer» C. 6 AT | |
| 78. |
The magnetism left in the iron after exciting field has been removed is known as? |
| A. | permeance |
| B. | residual magnetism |
| C. | susceptance |
| D. | reluctance |
| Answer» C. susceptance | |
| 79. |
What is the magnitude and the direction of force per 1.1m length of a pair of conductors of a direct current linecarrying 10 amperes and spaced 100 mm apart ? |
| A. | 22 x 10"8 N |
| B. | 22 x 10"7 N |
| C. | 22 x 10-6 N |
| D. | 22 x 10"5 N |
| Answer» E. | |
| 80. |
What is the magneto-motive force (mmf) of a wire with 8 turns carrying three amperes of current? |
| A. | 2,400 At |
| B. | 240 At |
| C. | 24 At |
| D. | 2.4 At |
| Answer» D. 2.4 At | |
| 81. |
A 200 turn coil having an axial length of 30 mm and a radius of 10 mm is pivoted in a magnetic field having a flux density of 0.8 T. If the coil carries a current of 0.5 A, the torque acting on the coil will be [Hint. Torque = 2BIlNr N-m] |
| A. | 8 N-m |
| B. | 0.48 N-m |
| C. | 0.048 N-m |
| D. | 0.0048 N-m |
| Answer» D. 0.0048 N-m | |
| 82. |
Core of an electromagnet should have |
| A. | low coercivity |
| B. | high susceptibility |
| C. | both of the above |
| D. | none of the above |
| Answer» D. none of the above | |
| 83. |
The use of permanent magnets is. not made in |
| A. | magnetoes |
| B. | energy meters |
| C. | transformers |
| D. | loud-speakers |
| Answer» D. loud-speakers | |
| 84. |
Susceptibility is positive for |
| A. | non-magnetic substances |
| B. | diamagnetic substances |
| C. | ferromagnetic substances |
| D. | none of the above |
| Answer» D. none of the above | |
| 85. |
How does the magnetic compass needle behave in a magnetic field? |
| A. | It assures a position right angle to magnetic field |
| B. | It starts rotating |
| C. | It assures a position which follows a line of magnetic flux |
| D. | None of the above |
| Answer» D. None of the above | |
| 86. |
Which of the following is the unit of magnetic flux density? |
| A. | Weber |
| B. | Lumens |
| C. | Tesla |
| D. | None of the above |
| Answer» D. None of the above | |
| 87. |
A 300 mm long conductor is carrying a current of 10 A and is situated at right angles to a magnetic field having a flux density of 0.8 T ; the force on the conductor will be |
| A. | 240 N |
| B. | 24 N |
| C. | 2.4 N |
| D. | 0.24 N |
| Answer» D. 0.24 N | |
| 88. |
For a given wire-wound core, an increase in current through the coil |
| A. | Reverses the flux lines |
| B. | Decreases the flux density |
| C. | Increases the flux density |
| D. | Causes no change in flux density |
| Answer» D. Causes no change in flux density | |
| 89. |
The magnetic materials exhibit the property of magnetisation because of |
| A. | orbital motion of electrons |
| B. | spin of electrons |
| C. | spin of nucleus |
| D. | either of these |
| Answer» D. either of these | |
| 90. |
When two ends of a circular uniform wire are joined to the terminals of a battery, the field at the center of the circle |
| A. | will be zero |
| B. | will be infinite |
| C. | will depend on the amount of e.m.f. applied |
| D. | will depend on the radius of the circle |
| Answer» E. | |
| 91. |
Substances which have permeability less than the permeability of free space are known as |
| A. | Ferromagnetic |
| B. | Paramagnetic |
| C. | Diamagnetic |
| D. | Bipolar |
| Answer» D. Bipolar | |
| 92. |
The unit of flux is the same as that of |
| A. | reluctance |
| B. | resistance |
| C. | permeance |
| D. | pole strength |
| Answer» E. | |
| 93. |
Materials subjected to rapid reversal of magnetism should have |
| A. | large area oiB-H loop |
| B. | high permeability and low hysteresis loss |
| C. | high co-ercivity and high retentivity |
| D. | high co-ercivity and low density |
| Answer» C. high co-ercivity and high retentivity | |
| 94. |
Which of the following is not a unit of flux? |
| A. | Maxwell |
| B. | Telsa |
| C. | Weber |
| D. | All of the above |
| Answer» C. Weber | |
| 95. |
The ratio of intensity of magnetisation to the magnetisation force is known as |
| A. | flux density |
| B. | susceptibility |
| C. | relative permeability |
| D. | none of the above |
| Answer» C. relative permeability | |