MCQOPTIONS
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MCQOPTIONS
This section includes 91 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. |
Which among the following, is a correct expression for µ₀. |
| A. | µ₀=BH |
| B. | µ₀=B/H |
| C. | µ₀=H/B |
| D. | µ₀=BH² |
| Answer» C. µ₀=H/B | |
| 52. |
A substance whose relative permeability is less than the permeability of free space is? |
| A. | Diamagnetic |
| B. | Paramagnetic |
| C. | Ferromagnetic |
| D. | Not a magnetic substance |
| Answer» B. Paramagnetic | |
| 53. |
Diamagnetic substances have relative permeability_____________ |
| A. | Greater than 1 |
| B. | Less than 1 |
| C. | Equal to 1 |
| D. | Zero |
| Answer» C. Equal to 1 | |
| 54. |
Which of the following expressions is correct with respect to relative permeability? |
| A. | B = µᵣµ₀/H |
| B. | B = µᵣµ₀H |
| C. | B = µᵣ/µ₀H |
| D. | B = µᵣµ₀/H² |
| Answer» C. B = µᵣ/µ₀H | |
| 55. |
The equivalent of the current I in magnetic ohm’s law is? |
| A. | Flux |
| B. | Reluctance |
| C. | MMF |
| D. | Resistance |
| Answer» B. Reluctance | |
| 56. |
Magnetic field exists along which of the following? |
| A. | Moving charges |
| B. | Stationary charges |
| C. | Copper |
| D. | Iron |
| Answer» B. Stationary charges | |
| 57. |
Materials having good retentivity are? |
| A. | Strong magnets |
| B. | Weak magnets |
| C. | Temporary magnets |
| D. | Permanent magnets |
| Answer» E. | |
| 58. |
What is a permeable substance? |
| A. | Any good conductor |
| B. | Any bad conductor |
| C. | Any strong magnet |
| D. | Any substance through which the magnetic lines of force can pass easily |
| Answer» E. | |
| 59. |
When an electric current flows out of the page, what is the direction of the magnetic field? |
| A. | Clockwise |
| B. | Anti-clockwise |
| C. | Cannot be determined |
| D. | Parallel to the current |
| Answer» C. Cannot be determined | |
| 60. |
A ring having a cross-sectional area of 500 mm2, a circumference of 400 mm and ?=800microWb has a coil of 200 turns wound around it. Relative permeability of ring is 380. Calculate the reluctance. |
| A. | 1.68 * 10-4A/Wb |
| B. | 1.68 * 104 A/Wb |
| C. | 1.68 * 106 A/Wb |
| D. | 1.68 * 10-6A/Wb |
| Answer» D. 1.68 * 10-6A/Wb | |
| 61. |
A ring having a cross-sectional area of 500 mm2, a circumference of 400 mm and ?=800microWb has a coil of 200 turns wound around it. Relative permeability of ring is 380. Calculate the magnetomotive force. |
| A. | 1442At |
| B. | 1342At |
| C. | 1432At |
| D. | 1344At |
| Answer» E. | |
| 62. |
As the magnetic flux density increases, the reluctance _____________ |
| A. | Increases |
| B. | Decreases |
| C. | Remains the same |
| D. | Becomes zero |
| Answer» C. Remains the same | |
| 63. |
A ring having a cross-sectional area of 500 mm2, a circumference of 400 mm and ?=800microWb has a coil of 200 turns wound around it. Calculate the flux density of the ring. |
| A. | 1.6T |
| B. | 2.6T |
| C. | 3.6T |
| D. | 4.6T |
| Answer» B. 2.6T | |
| 64. |
Calculate the reluctance when the magnetomotive force is 10A turns and the flux is 5Wb. |
| A. | 0.5A/Wb |
| B. | 5A/Wb |
| C. | 10A/Wb |
| D. | 2A/Wb |
| Answer» E. | |
| 65. |
What is MMF? |
| A. | Magnetic Machine Force |
| B. | Magnetomotive Force |
| C. | Magnetic Motion Force |
| D. | Magnetomotion Force |
| Answer» C. Magnetic Motion Force | |
| 66. |
A ring having a cross-sectional area of 500 mm2, a circumference of 400 mm and ?=800microWb has a coil of 200 turns wound around it. Relative permeability of ring is 380. Calculate the magnetising current. |
| A. | 6.7A |
| B. | 7.7A |
| C. | 7.6 |
| D. | 6.1A |
| Answer» B. 7.7A | |
| 67. |
Reluctance is ________________ to the area of cross section the material. |
| A. | Directly proportional |
| B. | Inversely proportional |
| C. | Not related |
| D. | Equal |
| Answer» C. Not related | |
| 68. |
As the temperature increases beyond the Curie temperature, the relative susceptibility of ferromagnetic materials? |
| A. | Increases |
| B. | Decreases |
| C. | Remains constant |
| D. | Becomes zero |
| Answer» C. Remains constant | |
| 69. |
Paramagnetic substances have relative permeability_____________ |
| A. | Greater than 1 |
| B. | Less than 1 |
| C. | Equal to 1 |
| D. | Zero |
| Answer» B. Less than 1 | |
| 70. |
Reluctance is ________________ to the length of the material. |
| A. | Directly proportional |
| B. | Inversely proportional |
| C. | Not related |
| D. | Reluctance is ________________ to the length of the material. |
| Answer» B. Inversely proportional | |
| 71. |
Which among the following, is a correct expression for µ0. |
| A. | µ0=BH |
| B. | µ0=B/H |
| C. | µ0=H/B |
| D. | µ0=BH2 |
| Answer» C. µ0=H/B | |
| 72. |
Calculate the magnetic flux density if the magnetic field strength is 3A/m. |
| A. | 4*pi*10-7T |
| B. | 8*pi*10-7T |
| C. | 10*pi*10-7T |
| D. | 12*pi*10-7T |
| Answer» E. | |
| 73. |
Calculate the magnetic field strength if the magnetic flux density is 4*piT. |
| A. | 10-7/16*pi2A/m |
| B. | 10-7A/m |
| C. | 107A/m |
| D. | 10-7A |
| Answer» D. 10-7A | |
| 74. |
A substance whose permeability is more than the permeability of free space is? |
| A. | Diamagnetic |
| B. | Paramagnetic |
| C. | Ferromagnetic |
| D. | Both paramagnetic and ferromagnetic |
| Answer» E. | |
| 75. |
Calculate the magnetic flux density if the magnetic field strength is 2A/m. |
| A. | 4*pi*10-7T |
| B. | 8*pi*10-7T |
| C. | 10*pi*10-7T |
| D. | 12*pi*10-7T |
| Answer» C. 10*pi*10-7T | |
| 76. |
A substance whose relative permeability is more than the permeability of free space is? |
| A. | Diamagnetic |
| B. | Paramagnetic |
| C. | Ferromagnetic |
| D. | Both paramagnetic and ferromagnetic |
| Answer» E. | |
| 77. |
Unit of MMF is ______________ |
| A. | A/m |
| B. | A-m |
| C. | A |
| D. | unitless |
| Answer» D. unitless | |
| 78. |
The relation between the direction of current and the direction of magnetic field is? |
| A. | Same direction |
| B. | Opposite direction |
| C. | Perpendicular |
| D. | Unrelated |
| Answer» D. Unrelated | |
| 79. |
Which, among the following, have positive susceptibility? |
| A. | Diamagnetic |
| B. | Paramagnetic |
| C. | Ferromagnetic |
| D. | Both paramagnetic and ferromagnetic |
| Answer» E. | |
| 80. |
Permeability of free space is also known as _________ |
| A. | Magnetic constant |
| B. | Electric constant |
| C. | Electrostatic constant |
| D. | Magnetostatic constant |
| Answer» B. Electric constant | |
| 81. |
Magnetomotive force is equal to__________________ |
| A. | current * number of turns |
| B. | current / number of turns |
| C. | current / number of turns per unit length |
| D. | current * number of turns per unit length |
| Answer» B. current / number of turns | |
| 82. |
The B/H characteristics can be determined using _______ |
| A. | Ammeter |
| B. | Fluxmeter |
| C. | Voltmeter |
| D. | Multimeter |
| Answer» C. Voltmeter | |
| 83. |
The B/H curve can be used to determine? |
| A. | Iron loss |
| B. | Hysteresis loss |
| C. | Voltage loss |
| D. | Eddy current loss |
| Answer» C. Voltage loss | |
| 84. |
B/H curve shows the relationship between? |
| A. | Magnetic field strength and magnetic flux |
| B. | Magnetic field strength and magnetic flux density |
| C. | Current and magnetic flux density |
| D. | Voltage and magnetic flux density |
| Answer» C. Current and magnetic flux density | |
| 85. |
What is a PMMC instrument? |
| A. | Permanent moving magnet coil instrument |
| B. | Permanent machine magnet coil instrument |
| C. | Permanent moving machine coil instrument |
| D. | Premature moving magnet coil instrument |
| Answer» B. Permanent machine magnet coil instrument | |
| 86. |
PMMC instruments can be used as a fluxmeters by _______ |
| A. | Using a low resistance shunt |
| B. | Removing the control spring |
| C. | Making the control springs having a large moment of inertia |
| D. | Using a high resistance in series |
| Answer» C. Making the control springs having a large moment of inertia | |
| 87. |
The B/H ratio is not constant for ________ |
| A. | Diamagnetic materials |
| B. | Ferromagnetic materials |
| C. | Paramagnetic materials |
| D. | Non-magnetic materials |
| Answer» C. Paramagnetic materials | |
| 88. |
Why is the coil of a ballistic galvanometer wound on a non- metallic former? |
| A. | To minimise damping when high resistance is connected in series |
| B. | To maximise damping when high resistance is connected in series |
| C. | To minimise damping when high resistance is connected in parallel |
| D. | To maximise damping when high resistance is connected in parallel |
| Answer» B. To maximise damping when high resistance is connected in series | |
| 89. |
Hysteresis loss is determined from _______ |
| A. | B/H curve |
| B. | H/B curve |
| C. | BH curve |
| D. | B2H curve |
| Answer» D. B2H curve | |
| 90. |
The ballistic galvanometer is usually lightly damped so that ________ |
| A. | It can oscillate |
| B. | It will remain stable |
| C. | Amplitude of the first swing is very large |
| D. | Amplitude of the first swing is very small |
| Answer» D. Amplitude of the first swing is very small | |
| 91. |
When using a fluxmeter, if the flux changes from F to -F, what happens to the current? |
| A. | Becomes zero |
| B. | Becomes infinity |
| C. | Remains the same |
| D. | Reverses |
| Answer» E. | |