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| Engineering Reviewer - Electricity and Magnetism Fundamentals |
Electricity and Magnetism FundamentalsMultiple Choice Questions
Electricity and Magnetism Fundamentals
51. The ratio of the permeability of material to the permiability of air or vacuum.
A. Relative permeability
B. Relative permitivity
C. Relative conductivity
D. Relative reluctivity
52. Permeance is analogous to
A. Conductance
B. Reluctance
C. Admittance
D. Resistance
53. The property of magnetic materials of retaining magnetism after withdrawal of the magnetizing force is known as
A. Retentivity
B. Reluctivity
C. Resistivity
D. Conductivity
54. The quantity of magnetism retained by a magnetic material after withdrawal of the magnetizing force is called
A. Leftover magnetism
B. Hysteresis
C. Residual magnetism
D. Coercivity
55. The amount of magnetizing force to counter balance the residual magnetism of a magnetic material is referred to as
A. Reluctivity
B. Susceptivity
C. Coercivity
D. Retentivity
56. The ratio of the total flux (flux in iron path) to the useful flux (flux in air gap)
A. Leakage flux
B. Leakage current
C. Leakage coefficient
D. Leakage factor
57. Defined as the number of lines per unit area through any substance in a plane at right angles to the lines of force
A. Flux
B. Flux lines
C. Flux density
D. Flux intensity
58. Defined as the flux density produced in it due to its own induced magnetism
A. Magnetic field intensity
B. Electric field intensity
C. Electromagnetic field intensity
D. Intensity magnetization
59. The force acting on a unit n- pole placed at that point is called
A. Magnetic field intensity
B. Electric field intensity
C. Electromagnetic field intensity
D. Intensity magnetization
60. The ratio between the intensity of magnetization produced in a substance to the magnetizing force producing it
A. Magnetic Reluctivity
B. Magnetic Resistivity
C. Magnetic susceptibility
D. Magnetic conductivity
61. The lagging effect between flux density of the material and the magnetizing force applied
A. Permeance
B. Eddy current
C. Hysteresis
D. Reluctance
62. Refers to the magnetic lines
A. Flux
B. Hysteresis
C. Current
D. Magnetomotive force
63. Refers to the non- metallic materials that have the ferromagnetic properties of iron.
A. Ferrites
B. Ferromagnetic
C. Diamagnetic
D. Paramagnetic
64. The air space between poles of magnets
A. Air gap
B. Free space
C. Vacuum
D. Atmosphere
65. One that has magnetic poles produced by internal atomic structure with no external current necessary
A. Diamagnetic
B. Permanent magnets
C. Paramagnetic
D. Electromagnetic
66. Magnetic effects of the earth as a huge magnet with north and south poles.
A. Diamagnetic
B. Ferromagnetic
C. Terrestrial magnetism
D. Terrestrial ferromagnetism
67. Used to maintain strength of magnetic field
A. Container
B. Air gap
C. Keeper
D. Source
68. All magnetic field originates from
A. moving electric charge
B. Iron atoms
C. Magnetic domain
D. Permanent magnets
69. Magnetic fields do not interact with
A. Moving permanent magnets
B. Stationary permanent magnets
C. Moving electric charges
D. Stationary electric charges
70. The magnetic field inside a solenoid
A. is zero
B. is uniform
C. increases with distance from the axis
D. decreases with distance from the axis
71. When the ferromagnetic substance is inserted in a current- carrying solenoid, the magnetic field is
A. Greatly decreased
B. Greatly increased
C. Slightly decreased
D. Slightly increased
72. The magnetic field of a bar magnet most closely resembles the magnetic field of
A. a horseshoe magnet
B. a straight current- carrying wire
C. a stream of electrons moving parallel to one another
D. a current- carrying wire loop
73. The magnetic field of a magnetized iron bar when strongly heated
A. Becomes weaker
B. Becomes stronger
C. Reverses in direction
D. is unchanged
74. A permanent magnet does not exert a force on
A. an unmagnetized iron bar
B. a magnetized iron bar
C. a moving electric charge
D. a stationary electric charge
75. A current if flowing east along a power line. If the earth’s field is neglected, the direction of the magnetic field below it is
A. North
B. South
C. East
D. West
76. The emf produced in a wire by its motion across a magnetic field does not depend upon the
A. Diameter of the wire
B. Length of the wire
C. Orientation of the wire
D. Flux density of the field
77. The induced emf in a wire loop that is moved parallel to a uniform magnetic field is
A. Zero
B. Dependent on the area of the loop
C. Dependent on the shape of the loop
D. Dependent on the magnitude of the field
78. When a wire loop is rotated in a magnetic field the direction of the induced emf changes one in every _______ revolution
A. 1/3
B. 1/2
C. 1/4
D. 2/3
79. The magnetic flux through a wire loop in a magnetic field does not depend on
A. The area of the loop
B. The magnitude of the field
C. The shape of the loop
D. The angle between the plane of the loop and the direction
80. Steel is hard to magnetize because of its
A. Low permeability
B. High permeability
C. High density
D. High retentivity
81. Paramagnetic substance has a relative permeability of
A. Slightly less than one
B. Equal to one
C. Slightly equal to one
D. Very much greater than one
82. A group of magnetically aligned atoms is called
A. Range
B. Lattice
C. Domain
D. Crystal
83. The force between two magnetic poles varies with the distance between them. The variation is ______ to the square of that distance.
A. Equal
B. Greater than
C. Directly proportional
D. Inversely proportional
84. Permeability means
A. The conductivity of the material for magnetic lines of force
B. The magnetization test in the material after exciting field has been removed
C. The strength of an electromagnet
D. The strength of the permanent magnet
85. ______ is an electromagnet with its core in the form of a close magnetic ring.
A. Solenoid
B. Paraboloid
C. Toroid
D. Cycloid
86. A magnetic material losses its ferromagnetic properties at a point called
A. Curie temperature
B. Inferred absolute temperature
C. Room temperature
D. Absolute temperature
87. Small voltages generated by a conductor with current in an external magnetic field.
A. Skin effect
B. Magnetic effect
C. Hall effect
D. Flywheel Effect
88. The emission of electrons from hot bodies is called
A. Radiation effect
B. Edison effect
C. Skin effect
D. Half effect
89. The ability of a mechanically stressed ferromagnetic wire to recognize rapid switching of magnetization when subjected to a dc magnetic field.
A. Wartheim effect
B. Wiedemann effect
C. Wiegand effect
D. Edison effect
90. An effect which is generally used in the gausameter to measure flux density.
A. Skin effect
B. Magnetic effect
C. Hall effect
D. Flywheel effect
91. The contribution to the ionization in an ionization chamber by electrons liberated from the walls.
A. Skin effect
B. Walt effect
C. Hall effect
D. Edison effect
92. The tiniest element of matter
A. Atom
B. Proton
C. Electron
D. Neutron
93. All matters (gas, liquid and solid) are composed of
A. Neutrons
B. Particles
C. Electrons
D. Atoms
94. The simplest type of atom to exist is the ______ atom.
A. Helium
B. Hydrogen
C. Boron
D. Oxygen
95. What revolves about the positive nucleus in a definite orbit?
A. Atom
B. Proton
C. Electron
D. Neutron
96. The uncharged particles which have no effect on its atomic charge.
A. Nucleons
B. Electrons
C. Protons
D. Neutrons
97. The diameter of a hydrogen atom is approximately ______ cm.
A. 1.1 x 10^-6
B. 1.1 x 10^-7
C. 1.1 x 10^-8
D. 1.1 x 10^-9
98. The K shell or the first shell has how many permissible number of orbiting electrons?
A. 1
B. 2
C. 3
D. 4
99. Germanium atom has ______ protons and ______ electrons.
A. 32, 32
B. 32, 42
C. 42, 32
D. 34, 34
100. A germanium atom has an atomic weight of 72. How many neutrons are there?
A. 32
B. 40
C. 34
D. 36
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