WorksheetsElectricity and Magnetism Fundamentals
Total questions: 500
Worksheet time: 4hrs 10mins
Name
Class
Date
1.
What is the diameter of an atom?
a)
About 10^-10 m
b)
About 10^-10 cm
c)
About 10^-10 mm
d)
About 10^-10 µm
2.
The magnitude of the induced emf in a coil is directly proportional to the rate of change of flux linkages. This is known as
a)
Joule's Law
b)
Faraday's second law of electromagnetic induction
c)
Faraday's first law of electromagnetic induction
d)
Coulomb's Law
3.
The force of attraction or repulsion between two magnetic poles is inversely proportional to the square of the distance between them. This is known as
a)
Newton's first law
b)
Faraday's first law of electromagnetic induction
c)
Coulomb's first law
d)
Coulomb's second law
4.
The net electrical charge in an isolated system remains constant. This is known as
a)
Law of conservation of charge
b)
Coulomb's first law
c)
Coulomb's second law
d)
Law of conservation of energy
5.
The point in a magnet where the intensity of magnetic lines of force is maximum
a)
Magnetic pole
b)
South pole
c)
North pole
d)
Unit pole
6.
The emf induced in a coil due to the change of its own flux linked with it is called
a)
Mutually induced emf
b)
Dynamically induced emf
c)
Statically induced emf
d)
Self induced emf
7.
If the solenoid is gripped by the right hand with the fingers pointing the direction of current flow, the outstretched thumb will then point the north pole. This is known as
a)
Right hand rule
b)
Helix rule
c)
End rule
d)
Cork screw rule
8.
The phenomenon by which a subtracts pieces of iron
a)
Magnetism
b)
Electromagnetism
c)
Naturalism
d)
Materialism
9.
A law that states that the current in a thermionic diode varies directly with the three-halves power of anode voltage and inversely with the square of the distance between the electrodes, provided operating conditions are such that the current is limited only by the space charge
a)
Hall's law
b)
Joule's law
c)
Child's law
d)
Coulomb's law
10.
Who developed the electromagnetic theory of light in 1862?
a)
Heinrich Rudolf Hertz
b)
Wilhelm Rontgen
c)
James Clerk Maxwell
d)
Andre Ampere
11.
The space outside the magnet where its pole have a force of attraction or repulsion on a magnetic pole is called
a)
Magnetic field
b)
Electric field
c)
Electromagnetic field
d)
Free Space Field
12.
States that the ratio of the thermal conductivity is proportional to the absolute temperature for all metals
a)
Wien's displacement law
b)
Hartleys law
c)
Hall's law
d)
Wiedemann Franz law
13.
Materials whose permeabilities are slightly greater than that of free space
a)
Paramagnetic
b)
Non- magnetic
c)
Ferromagnetic
d)
Diamagnetic
14.
Who discovered the relationship between magnetism and electricity that serves as the foundation for the theory of electromagnetism?
a)
Luigi Galvani
b)
Hans Christian Oersted
c)
Andre Ampere
d)
Charles Coulomb
15.
Materials that have very high permeabilities (hundreds and even thousands times of that of free space)
a)
Paramagnetic
b)
Non- magnetic
c)
Ferromagnetic
d)
Diamagnetic
16.
If on looking at any one end of a solenoid the direction of current flow is found to be clockwise then the end under observation is a south pole. This is known as
a)
Right hand rule
b)
Left hand rule
c)
Cork screw rule
d)
End Rule
17.
The straight line passing through the two poles of magnet is called
a)
Real axis
b)
Cartesian axis
c)
Magnetic axis
d)
Imaginary axis
18.
Who discovered the most important electrical effects which is the magnetic effect?
a)
Hans Christian Oersted
b)
Sir Charles Wheatstone
c)
Georg Ohm
d)
James Clerk Maxwell
19.
Define as that pole which when placed in air from a similar and equal pole repels it with a force of newtons
a)
North pole
b)
South pole
c)
Unit pole
d)
Magnetic pole
20.
Referred to as the specific reluctance of a material
a)
Resistivity
b)
Reluctivity
c)
Conductivity
d)
Permeability
21.
Which of the following magnetic materials can be easily magnetized in both direction?
a)
Soft magnetic materials
b)
Hard magnetic materials
c)
High hysteresis loss materials
d)
Low hysteresis loss materials
22.
The force which set ups or tends to set up magnetic flux in a magnetic circuit
a)
Dynamic force
b)
Electromotive force
c)
Potential difference
d)
Magnetomotive force
23.
A law establishing the fact that the algebraic sum of the rises and drops of the mmf around a closed loop of a magnetic circuit is equal to zero
a)
Kirchhoff's circuital law
b)
Maxwell's circuital law
c)
Ampere's circuital law
d)
Coulomb's circuital law
24.
The phenomenon by which a magnetic substance becomes a magnet when it is place near a magnet
a)
Magnetic effect
b)
Magnetic phenomenon
c)
Magnetic induction
d)
Electromagnetic induction
25.
The magnetic potential in a magnetic circuit can be measured in terms of
a)
Mmf
b)
Emf
c)
Farad
d)
Coulomb
26.
Who demonstrated that there are magnetic effects around every current-carrying conductor and that current-carrying conductors can attract and repel each other just like magnets?
a)
Luigi Galvani
b)
Hans Christian Oersted
c)
Charles Coulomb
d)
Andre Ampere
27.
Lenz' law states that the direction of the induced emf and hence current
a)
Is determined by the rate of current flux
b)
Is found by the right hand rule
c)
Is found by the left hand rule
d)
Always opposes the cause producing it
28.
Whenever a flux inking a coil or current changes, an emf is induced in it. This is known as
a)
Joule's Law
b)
Coulomb's Law
c)
Faraday's first law of electromagnetic induction
d)
Faraday's second law of electromagnetic induction
29.
Which of the following materials has permeability slightly less than that of free space?
a)
Paramagnetic
b)
Non- magnetic
c)
Ferromagnetic
d)
Diamagnetic
30.
The property of a material which opposes the creation of magnetic flux in it
a)
Resistance
b)
Reluctance
c)
Permeance
d)
Conductance
31.
Who discovered superconductivity in 1911?
a)
Kamerlingh Onnes
b)
Alex Muller
c)
Geory Bednorz
d)
Charles Coulomb
32.
A substance that attracts pieces iron
a)
Conductor
b)
Semiconductor
c)
Magnet
d)
All of the above
33.
The point in a magnet where the intensity of magnetic lines of force is maximum
a)
Magnetic pole
b)
South pole
c)
North pole
d)
Unit pole
34.
Lenz's law is the consequence of the law of conservation of
a)
Energy
b)
Charge
c)
Field lines
d)
Momentum
35.
Defined as a closed path in which magnetic induction or flux flows
a)
Electric circuit
b)
Magnetic circuit
c)
Electronic circuit
d)
Electromagnetic circuit
36.
Who demonstrated the theory of electromagnetic induction in 1831?
a)
Michael Faraday
b)
Andre Ampere
c)
James Clerk Maxwell
d)
Charles Coulomb
37.
Who discovered that a current-carrying conductor would move when placed in a magnetic field?
a)
Michael Faraday
b)
Andre Ampere
c)
Hans Christian Oersted
d)
Gustav Robert Kirchhoff
38.
Whenever a conductor cuts magnetic flux, an emf is induced in it. This is known as
a)
Coulomb's law
b)
Joule's law
c)
Faraday's law
d)
Ohm's law
39.
A law that states that the polarity of the induced voltage will oppose the change in magnetic flux causing the induction
a)
Joule's law
b)
Faraday's law
c)
Coulomb's law
d)
Lenz' law
40.
If you hold the conductor with right hand so that the stretched thumb points in the direction of the current, then encircling fingers will give the direction of magnetic lines of force round the conductor. This is known as
a)
Left hand cork screw rule
b)
Right hand cork screw rule
c)
Left hand rule
d)
Right hand rule
41.
If the right handed bottle-opener cork screw is assumed to be along the conductor so as to advance in the direction of current flow, the motion of its handle will indicate the direction of magnetic flux produced around the conductor. This is known as
a)
Right hand rule
b)
Left hand rule
c)
Cork screw rule
d)
End rule
42.
The process by which an emf and hence current is generated or induced in a conductor when there is a change in the magnetic flux linking the conductor is called
a)
Electromagnetic induction
b)
Mutual induction
c)
Faraday's law
d)
Electromagnetic interference
43.
The emf induced in a coil due to the changing current of another neighboring coil is called
a)
Mutually induced emf
b)
Self induced emf
c)
Statically induced emf
d)
Dynamically induced emf
44.
When a conductor is stationary and the magnetic field is moving or changing the emf induced is called
a)
Statically induced emf
b)
Mutually induced emf
c)
Self induced emf
d)
Dynamically induced emf
45.
Which of the following is a natural magnet?
a)
Steel
b)
Magnesia
c)
Lodestone
d)
Soft iron
46.
The branch of Engineering which deals with the magnetic effect of electric current is known as
a)
Magnetism
b)
Electromagnetism
c)
Electrical engineering
d)
Electronics engineering
47.
The total number of magnetic lines of force in a magnetic field is called
a)
Magnetic flux
b)
Magnetic flux density
c)
Magnetic flux intensity
d)
Magnetic potential
48.
The current of electric circuit is analogous to which quantity of a magnetic circuit
a)
Mmf
b)
Flux
c)
Flux density
d)
Reluctivity
49.
It is the reciprocal of reluctance and implies the case of readiness with which magnetic flux is developed
a)
Resistance
b)
Conductance
c)
Permeance
d)
Inductance
50.
The ability of a material to conduct magnetic flux through it
a)
Permittivity
b)
Reluctivity
c)
Conductivity
d)
Permeability
51.
The ratio of the permeability of material to the permeability of air or vacuum
a)
Relative permeability
b)
Relative permittivity
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)
2023-01-03 00:00:00
b)
2023-01-02 00:00:00
c)
2023-01-04 00:00:00
d)
2023-02-03 00:00:00
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
101.
How many neutrons does a copper atom have?
a)
32
b)
33
c)
34
d)
29
102.
Bonding of atoms that is due to the force of attraction between positive ions and a group of negative ions
a)
Ionic bond
b)
Covalent Bond
c)
Electrostatic Bond
d)
Metallic bond
103.
An alloy of 22 percent iron and 78 per cent nickel
a)
Permalloy
b)
Alnico
c)
Constantan
d)
Manganin
104.
An alloy of 40 percent iron and 60 percent nickel
a)
Alnico
b)
Permalloy
c)
Hipernik
d)
Manganin
105.
A commercial alloy of aluminum nickel, and iron with cobalt, copper and titanium added to produce about 12 grades
a)
Alnico
b)
Brass
c)
Aluminum
d)
Constantan
106.
The idea of preventing one component from affecting another through their common electric and magnetic field is referred to as
a)
Hall effect
b)
Grounding
c)
Shielding
d)
Limiting
107.
The physical motion resulting from the forces of magnetic fields is called
a)
Motor action
b)
Rotation
c)
Repulsion
d)
Torque action
108.
Flux linkages equals
a)
Flux times area of core
b)
Flux times number of turns times area of core
c)
Flux times number of turns times length of core
d)
Flux times number of turns
109.
Which of the following is a vector quantity?
a)
Magnetic potential
b)
Magnetic field intensity
c)
Magnetic permeability
d)
Flux density
110.
Which of the following electric quantities is vector in character?
a)
Field
b)
Charge
c)
Energy
d)
Potential Difference
111.
The quantity 10^6 Maxwell's is equivalent to one
a)
Weber
b)
Gauss
c)
Gilbert
d)
Tesla
112.
What is the unit of reluctance?
a)
Maxwell
b)
Gauss
c)
At/Wb
d)
Weber
113.
What is the SI unit of magnetic flux?
a)
Tesla
b)
Weber
c)
Maxwell
d)
Gauss
114.
What is the unit of magnetomotive force?
a)
Volt
b)
Tesla
c)
Ampere - turn
d)
Weber
115.
What is the cgs unit of magnetomotive force?
a)
Gilbert
b)
Ampere- turn
c)
Maxwell
d)
Weber
116.
The unit of flux is _____________ in cgs system
a)
Tesla
b)
Gilbert
c)
Maxwell
d)
Oersted
117.
Flux density is measured in
a)
Tesla
b)
Weber
c)
Ampere- turn
d)
Maxwell
118.
The customary energy unit in atomic and nuclear physics is
a)
Joule
b)
Volt- coulomb
c)
electron-volt
d)
Walt- second
119.
One ampere- turn is equivalent to __________ gilberts
a)
1.16
b)
1.26
c)
1.36
d)
1.46
120.
The magnetic flux of 2000 lines is how many Maxwells?
a)
1000
b)
2000
c)
4000
d)
8000
121.
How much is the flux in Weber in the above problem?
a)
2 x 10^-5
b)
2 x 10^-3
c)
2 x 10^5
d)
2 x 10^3
122.
One oersted (Oe) is equivalent to ________ Gb/cm
a)
1
b)
10
c)
100
d)
1000
123.
One electron volt (1 eV) is equivalent to ___________ joules
a)
1.3 x 10^-19
b)
1.4 x 10^-19
c)
1.5 x 10^-19
d)
1.6 x 10^-19
124.
An electron- volt (eV) is a unit of
a)
Energy
b)
Potential difference
c)
Charge
d)
Momentum
125.
The unit of electrical energy is
a)
Joule
b)
Watt- second
c)
Kilowatt- hour
d)
All of these
126.
Electrons at the outer shell are called
a)
Outer shell electrons
b)
Inner shell electrons
c)
Semiconductor electrons
d)
Valence electrons
127.
Which of the following has the least number of valence electrons?
a)
Conductor
b)
Semiconductor
c)
Insulator
d)
Semi- insulator
128.
A good conductor has how many valence electrons?
a)
1
b)
4
c)
2
d)
8
129.
Which element has four valence electrons?
a)
Conductor
b)
Insulator
c)
Semiconductor
d)
Semi- insulator
130.
A negative ion results when an atom gains an additional
a)
Electron
b)
Proton
c)
Neutron
d)
Atom
131.
An atom or a group of atoms that carries a net electric charge
a)
Positive ion
b)
Negative ion
c)
Ion
d)
Electron
132.
Hysteresis refers to the _______________ between flux density of the material and the magnetizing force applied
a)
Leading effect
b)
Ratio
c)
Equality
d)
Lagging effect
133.
Hydrogen is an example of a ____________ material
a)
Paramagnetic
b)
Diamagnetic
c)
Ferromagnetic
d)
Non- magnetic
134.
Cobalt is an example of a _____________ material
a)
Paramagnetic
b)
Diamagnetic
c)
Ferromagnetic
d)
Non- magnetic
135.
The evaporation of electrons from a heated surface is called
a)
Radiation
b)
Convection
c)
Thermionic emission
d)
Conduction
136.
Electron is a Greek word for
a)
amber
b)
Fire
c)
Stone
d)
Heat
137.
Gases whose particles are charged are known as
a)
Conductors
b)
Insulators
c)
Gaseous Conductors
d)
Plasma
138.
What principle states that each electron in an atom must have a different set of quantum numbers?
a)
Inclusion principle
b)
Exclusion principle
c)
Quantum principle
d)
Electron principle
139.
The energy stored in an electrostatic field or electromagnetic field is called
a)
Electromagnetic energy
b)
Kinetic energy
c)
Potential energy
d)
Rest energy
140.
Which of the following statements is TRUE?
a)
Silicon dioxide is a good
b)
The current carriers in conductors are valence electrons
c)
For conductors, the valence electron are strongly attracted to the nucleus
d)
The valence electrons are located in the nucleus of an atom
141.
How many electrons are needed in the valence orbit to give a material's stability?
a)
8
b)
4
c)
6
d)
5
142.
Residual magnetism refers to the flux density, which exists in the iron core when the magnetic field intensity is
a)
Minimized
b)
Reduced to zero
c)
Maximize
d)
Unity
143.
Magnetic intensity is a
a)
Phasor quantity
b)
Physical quantity
c)
Scalar quantity
d)
Vector quantity
144.
The core of a magnetic equipment uses a magnetic material with
a)
Least permeability
b)
Low permeability
c)
Moderate permeability
d)
High permeability
145.
Which of the following is a paramagnetic material?
a)
Carbon
b)
Copper
c)
Bismuth
d)
Oxygen
146.
The permeability of permalloy is
a)
Very much greater than permeability of air
b)
Slightly greater than permeability of air
c)
Slightly less than permeability of air
d)
Equal to the permeability of air
147.
A t/m is a unit of
a)
Mmf
b)
Emf
c)
Reluctance
d)
Magnetizing force
148.
The force between two magnetic poles is ____________ their poles strength
a)
equal to
b)
directly proportional to
c)
inversely proportional to
d)
directly proportional to the square root of
149.
The magnetic energy stored in an inductor is ______________ current
a)
Directly proportional to
b)
Inversely proportional to
c)
Directly proportional to the square of
d)
Inversely proportional to the square of
150.
One of the common application of an air- cored choke
a)
Radio frequency
b)
Audio frequency
c)
Power supply
d)
Power transformer
151.
How is mutual inductance between two coils decreased?
a)
By using a common core
b)
By moving the coils closer
c)
By moving the coils apart
d)
By increasing the number of turns of either coil
152.
A magnetic field is
a)
The current flow through space around a permanent magnet
b)
The force set up when current flows through a conductor
c)
The force that drives current through a resistor
d)
The force between the plates of a charged capacitor
153.
Ohm's law can be used only to a _____________ circuit or component
a)
Unilateral
b)
Exponential
c)
Trivalent
d)
Linear
154.
When the current flows, the magnetic field conductor is in what direction?
a)
The same as the current direction
b)
Opposite the current direction
c)
Omnidirectional
d)
In the direction determined by the left hand rule
155.
The magnetic field around the conductor is determined by the
a)
Size of the conductor
b)
Amount of current
c)
Current divided by the resistance
d)
Resistance divided by the current
156.
Back emf refers to the
a)
Current equal to the applied emf
b)
Opposing emf
c)
Current opposing the applied emf
d)
Voltage opposing the applied emf
157.
The magnetic flux through a coil changes. This results to the induced emf acting in a direction as to
a)
Oppose the change
b)
Aid the change
c)
Either oppose or aid the change
d)
Neither oppose nor aid the change
158.
A magnetic flux of 2.5 x 10^4 Wb through an area of 5 x 10^4 square meters results in
a)
5 Wb
b)
0.5 Tesla of flux density
c)
5 x 10^-5 Wb of flux
d)
5000 Tesla of flux density
159.
If a 20 V potential is applied across a relay coil with 50 turns having 1 Ω of resistance, the total magnetomotive producing magnetic flux in the circuit is
a)
10 Wb
b)
50 T
c)
1000 A t/m
d)
1000 A.t
160.
What is the reluctance of a magnetic path having a length of 2 x 10^-3 m and cross- sectional area of 2.5 x 10^-3 m^2?
a)
6366 A.t/Wb
b)
6000 A.t/Wb
c)
8 x 10^-3 A.t/Wb
d)
0.8 A.t/Wb
161.
Calculate the permeability (in T/t/m) of a magnetic material that has a relative permeability of 300
a)
3.78 x 10^-4
b)
3.78 x 10^-5
c)
3.78 x 10^-3
d)
3.78 x 10^-6
162.
Calculate the flux density that will be produced by the field intensity of 2000 t/m for a permeability of 126 x 10^-6 T/A.t/m
a)
0.252 G
b)
0.252 x 10^-2 T
c)
0.252 T
d)
0.252 x 10^-2 G
163.
How many turns are needed to produce a magnetomotive force of 1000 A.t for a coil with 6 amperes?
a)
6000 turns
b)
600 turns
c)
167 turns
d)
67 turns
164.
A 6- V battery is connected across a solenoid of 100 turns having a resistance of 2 Ω, Calculate the number of ampere turns?
a)
100
b)
50
c)
300
d)
600
165.
What determines the atomic number of an element?
a)
The number of protons
b)
The number of electrons
c)
The number of neutrons
d)
The number of neutrons and protons
166.
One of the solid structures in which the position of the atoms or ions are predetermined
a)
Crystalline solid
b)
Amorphous solid
c)
Polycrystalline solid
d)
Poly- amorphous solid
167.
Mmf in a magnetic circuit corresponds to ________ in an electric circuit
a)
Emf
b)
Voltage drop
c)
Electric Field Intensity
d)
Potential gradient
168.
What solid has no defined crystal structure except perhaps in the arrangement of the nearest neighboring atoms or ions?
a)
Crystalline
b)
Amorphous
c)
Polycrystalline
d)
Poly- amorphous
169.
Amorphous solid is also called
a)
Crystalline
b)
Non- crystalline
c)
Polycrystalline
d)
Homogenous
170.
A principle that states that only two electrons with different spins are allowed to exist in a given orbit
a)
Bohr's principle
b)
Pauli exclusion principle
c)
Avogadro's principle
d)
Coulomb's principle
171.
What bond is formed when one or more electrons in the outermost energy orbit of an atom are transferred to another?
a)
Ionic
b)
Covalent
c)
Metallic
d)
Van der Waals
172.
In electro-mechanical conversion devices like generators and motors the reason why a small air gap is left between the rotor and stator is to
a)
permit mechanical clearance
b)
increase flux density in air gap
c)
decrease the reluctance of magnetic path
d)
complete the magnetic path
173.
What bond is formed when electrons in the outermost energy orbits of the atoms are shared between two or more electrons?
a)
Ionic
b)
Covalent
c)
Metallic
d)
Van der Waals
174.
Why is it that the magnitude of magnetomotive force required for air gap is much greater than that required for iron part of a magnetic circuit?
a)
Because air is a gas
b)
Because air has the highest relative permeability
c)
Because air is a conductor of magnetic flux
d)
Because air has the lowest relative permeability
175.
What type of bond is formed when there exists some form of collective interactions between the (negatively charged) electrons and (positively charged) nuclei in a solid?
a)
Ionic
b)
Covalent
c)
Metallic
d)
Van der Waals
176.
Permeance of a magnetic circuit is ______________ the cross-sectional area of the circuit
a)
directly proportional to
b)
inversely proportional to
c)
dependent of
d)
independent of
177.
Formed when there exist distant electronic interactions between (opposite) charges present in the neighboring atoms or molecules
a)
Ionic bond
b)
Covalent bond
c)
Metallic bond
d)
Van der Waals bond
178.
Defined as the ratio of the volume occupied by the atoms or ions in a unit cell divided by the volume of the unit cell and is used to measure the compactness of a crystal
a)
Atomic packing factor (APF)
b)
Ionic Packing Ratio (IPR)
c)
Atomic compacting factor (ACF)
d)
Ionic compacting ratio (ICR)
179.
A factor used to correct for the electrostatic forces of the more distant ions in an ionic solid
a)
Avogadro's number
b)
Planck's constant
c)
Boltzmann's constant
d)
Madelung constant
180.
The conduction of electricity across the surface of a dielectric is called
a)
creepage
b)
skin effect
c)
surface effect
d)
crosstalk
181.
A magnetic circuit carries a flux φi in the iron part and a flux φg in the air gap. What is the leakage coefficient?
a)
φi/ φg
b)
φi × φg
c)
φg /φi
d)
φi + φg
182.
A law stating that the magnetic susceptibilities of most paramagnetic substances are inversely proportional to their absolute temperatures
a)
Curie's Law
b)
Child's Law
c)
CR Law
d)
Curie-Weiss Law
183.
The reluctance of the magnetic circuit is _______________ relative permeability of the material comprising the circuit
a)
directly proportional to
b)
inversely proportional to
c)
independent of
d)
dependent of
184.
A law relating between the magnetic and electric susceptibilities and the absolute temperatures which is followed b ferromagnets, antiferromagnets, non-polar ferroelectrics, antiferroelectrics and some paramagnets
a)
Curie's Law
b)
Child's Law
c)
CR Law
d)
Curie-Weiss Law
185.
Theory of ferromagnetic phenomena which assumes each atom is a permanent magnet which can turn freely about its center under the influence of applied field and other magnets
a)
Ewing's theory of ferromagnetism
b)
Oersted's ferromagnetism theory
c)
Maxwell's magnetic theory
d)
Ampere's circuital law
186.
The reluctance of a magnetic circuit varies with
a)
length × area
b)
area ÷ length
c)
length ÷ area
d)
length + area
187.
A theorem which states that an electric current flowing in a circuit produces a magnetic field at external points equivalent to that due to a magnetic shell whose bounding edge is the conductor and whose strength of the current
a)
Joule's law
b)
Faraday's law
c)
Volta's theorem
d)
Ampere's theorem
188.
What is the usual value of leakage coefficient for electrical machines?
a)
0.5 to 1
b)
1 to 5
c)
5 to 10
d)
1.15 to 1.25
189.
The science of adapting electronics to aerospace flight
a)
Avionics
b)
Aerotronics
c)
Aerodynamics
d)
Astrionics
190.
The reluctance of a magnetic circuit is not dependent on which of the following?
a)
Number of turns of coil
b)
Magnetomotive force
c)
Flux density in the circuit
d)
Current in the coil
191.
Another term for corona discharge
a)
Lightning
b)
Sparking
c)
Aurora
d)
Corona Effect
192.
The B-H curve for ____________ is a straight line passing through the origin
a)
cobalt
b)
air
c)
hardened steel
d)
soft iron
193.
The phenomenon that when an electric current passes through an anisotropic crystal, there is an absorption or liberation of heat due to the non-uniformity in current distribution
a)
Bridgman effect
b)
Corona effect
c)
Dember effect
d)
Destriau effect
194.
The B-H curve of ____________ is not a straight line
a)
air
b)
wood
c)
silicon steel
d)
soft iron
195.
If a magnetic flux cuts across 200 turns at a rate of 2 Wb/s, the induced voltage according to Faraday's law is about
a)
400 V
b)
100 V
c)
200 V
d)
600 V
196.
What is the SI unit of reluctance?
a)
At
b)
At/m
c)
N/Wb
d)
At/Wb
197.
A magnetizing force of 1000 AT/m will produce a flux density of ____________ in air
a)
1.257 mWb/m^2
b)
0.63 Wb/m^2
c)
1.257 Wb/m^2
d)
0.63 mWb/m^2
198.
Hysteresis loss can be reduced by one of the following
a)
Increasing mmf of the circuit
b)
Using material narrow hysteresis loop
c)
Using ferromagnetic core
d)
Laminating the magnetic circuit
199.
The core of a transformer heats up when its primary is fed from an ac source because of
a)
permeability
b)
ferromagnetism
c)
reluctance of core
d)
hysteresis loss
200.
Which of the following materials has the least hysteresis loop area?
a)
soft iron
b)
silicon steel
c)
hard steel
d)
wrought iron
201.
Core materials of a good relay have _____________ hysteresis loop
a)
large
b)
narrow
c)
very large
d)
very narrow
202.
The magnetic materials should have a large hysteresis loss for one of the following applications
a)
Transformers
b)
AC motors
c)
Permanent Magnets
d)
DC generators
203.
If the magnetic material is located within a coil through which alternating current (60 Hz frequency) flows, then __________ hysteresis loops will be formed every second
a)
60
b)
120
c)
30
d)
180
204.
There are how many compounds available in nature?
a)
105
b)
1000
c)
300000
d)
Unlimited
205.
Hysteresis is a phenomenon of ______________ in a magnetic circuit
a)
setting up constant flux
b)
lagging of H behind B
c)
lagging B behind H
d)
leading B ahead H
206.
What is the measure of the density and sign of the electric charge at a point relative to that at some time?
a)
Electric potential
b)
Electric charge
c)
Electric current
d)
Electric intensity
207.
__________ is a substance of whose molecules consist of the same kind of atom
a)
Mixture
b)
Compound
c)
Element
d)
Isotope
208.
Hipernik is an alloy containing __________ iron and __________ nickel
a)
40% ; 60%
b)
60% ; 40%
c)
50% ; 50%
d)
70% ; 30%
209.
The mass of proton is ____________ the mass of an electron
a)
equal to
b)
about 1837 times
c)
less than
d)
200 times
210.
What is the maximum number of electrons that can be accommodated in the last orbit of an atom?
a)
4
b)
2
c)
8
d)
18
211.
The electrons in the last orbit of an atom are called ____________ electrons
a)
free
b)
valence
c)
bound
d)
thermionic
212.
If the number of valence electrons of an atom is less than 4, the substance is called
a)
a conductor
b)
a semiconductor
c)
an insulator
d)
a superconductor
213.
If the number of valence electrons of an atom is more than 4, the substance is called
a)
a semiconductor
b)
a conductor
c)
an insulator
d)
a semi-insulator
214.
If the number of valence electrons of an atom is exactly 4, then the substance is called
a)
a semiconductor
b)
a conductor
c)
an insulator
d)
a cryogenic conductor
215.
If the number of valence electrons of an atom is less than 4, then the substance is probably
a)
a metal
b)
an insulator
c)
a non-metal
d)
a semiconductor
216.
One coulomb of charge consists of ____________ electrons
a)
624 × 10^16
b)
62.4 × 10^16
c)
6.24 × 10^16
d)
0.624 × 10^16
217.
A one cubic cm of copper has how many free electrons at room temperature?
a)
80 × 10^18
b)
8.5 × 10^22
c)
20 × 10^10
d)
50 × 10^20
218.
Electronic current in a wire is the flow of ____________ electrons
a)
free
b)
valence
c)
bound
d)
loose
219.
Electromotive force in a circuit
a)
causes free electrons to flow
b)
increases the circuit resistance
c)
maintains circuit resistance
d)
is needed to make the circuit complete
220.
The resistance of a material is ____________ its area of cross-section
a)
directly proportional
b)
independent of
c)
inversely proportional to
d)
equal to
221.
If the length and area of cross-section of a wire are doubled, then its resistance
a)
becomes four times
b)
becomes sixteen times
c)
remains the same
d)
becomes two times
222.
A length of wire has a resistance of 10 ohms. What is the resistance of a wire of the same material three times as long and twice the cross-sectional area?
a)
30 ohms
b)
20 ohms
c)
15 ohms
d)
7 ohms
223.
What is the SI unit of specific resistance or resistivity?
a)
Ohm-circular mil per inch
b)
Ohm-circular mil per foot
c)
Ohm-m
d)
Ohm-cm
224.
The resistivity of a conductor _____________ with an increase in temperature
a)
increases
b)
decreases
c)
remains the same
d)
becomes zero
225.
What is the SI unit of conductance?
a)
Siemens
b)
Mhos
c)
Ohms
d)
1/Ohms
226.
If the resistance of a material 2 m long and 2 m^2 in area of cross-section is 1.6 × 10^-8 Ω, then its resistivity is
a)
3.2 × 10^-8 Ω-m
b)
1.6 × 10^-8 Ω-m
c)
0.64 × 10^-8 Ω-m
d)
0.16 × 10^-8 Ω-m
227.
What is the SI unit of conductivity?
a)
Ohms/m
b)
Ohms-m
c)
Siemens-m
d)
Siemens/m
228.
The temperature coefficient of resistance of conductors is
a)
positive
b)
zero
c)
negative
d)
infinite
229.
The temperature coefficient of resistance of semiconductors is
a)
positive
b)
zero
c)
negative
d)
infinite
230.
What determines the value of the temperature coefficient of resistance of a material?
a)
length
b)
cross-sectional area
c)
volume
d)
nature and temperature
231.
The temperature coefficient of resistance of a conductor ______________ with an increase in temperature
a)
increases
b)
decreases
c)
remains the same
d)
becomes negative
232.
The temperature coefficient of resistance of insulators is
a)
zero
b)
negative
c)
positive
d)
infinite
233.
The temperature coefficient of resistance of eureka is
a)
positive
b)
negative
c)
almost zero
d)
infinite
234.
If the value of α0 a conductor is 1/234 per oC, then the value of α18 is
a)
1/218 per °C
b)
1/252 per °C
c)
1/272 per °C
d)
1/273 per °C
235.
If the value of α25 a conductor is 1/255 per °C, then the value of α20 is
a)
1/300 per °C
b)
1/250 per °C
c)
1/230 per °C
d)
1/260 per °C
236.
If the value of α25 of a conductor is 1/230 per °C, then the value of α0 is
a)
1/180 per °C
b)
1/150 per °C
c)
1/280 per °C
d)
1/230 per °C
237.
Ohm's law cannot be applied to which material?
a)
Copper
b)
Silver
c)
Silicon carbide
d)
Aluminum
238.
What is the practical unit of electrical energy?
a)
Watt
b)
Kilowatt-hour
c)
Kilowatt-second
d)
Megawat-hour
239.
A 200-watt lamp working for 24 hours will consume approximately ____________ units
a)
50
b)
5
c)
24
d)
0.5
240.
The hot resistance of an incandescent lamp is about _____________ its cold resistance
a)
10 times
b)
100 times
c)
5 times
d)
50 times
241.
Under ordinary conditions, a body is considered
a)
positively charged
b)
neutral
c)
negatively charged
d)
stable
242.
A positively charged body has
a)
deficit of electrons
b)
excess of neutrons
c)
excess of electrons
d)
deficit of protons
243.
A negatively charge body has
a)
deficit of electrons
b)
excess of protons
c)
excess of electrons
d)
deficit of neutrons
244.
This paper does not exhibit electricity because it contains the same number of
a)
protons and electrons
b)
neutrons and electrons
c)
neutrons and positrons
d)
atoms
245.
What is the value of the absolute permittivity of air?
a)
8.854 μF/m
b)
8.854 × 10^-12 mF/m
c)
8.854 × 10^-12 F/m
d)
8.854 × 10^-12 μF/m
246.
What is the relative permittivity of air?
a)
0
b)
1
c)
8.854 × 10^-12
d)
4π × 10^-7
247.
If two similar charges 1 coulomb each are placed 1 m apart in air, then the force of repulsion is
a)
8 × 10^6 N
b)
9 × 10^9 N
c)
10^6 N
d)
5 × 10^6 N
248.
If the relative permittivity of a material is 10, then its permittivity is
a)
4π × 10^-7 F/m
b)
4π × 10^-6 F/m
c)
8.854 × 10^-11 F/m
d)
8.854 × 10^-12 F/m
249.
The force between two charges placed a given distance apart _____________ as the relative permittivity of the medium is increased
a)
increases
b)
decreases
c)
remains unchanged
d)
becomes infinite
250.
What is another name for relative permittivity?
a)
Dielectric strength
b)
Electric intensity
c)
Potential gradient
d)
Dielectric constant
251.
The relation between absolute permittivity of air (ε0), absolute permeability of air (μ0) and velocity of light (c) is given by
a)
μ0ε0 = c^2
b)
μ0ε0 = c
c)
1/μ0ε0 = c
d)
1/μ0ε0 = c^2
252.
The dielectric constant of most materials lies between
a)
1 and 10
b)
10 and 20
c)
20 and 50
d)
50 and 100
253.
A test charge means a charge of
a)
-1 C
b)
1 electron
c)
+1 C
d)
-20 C
254.
Electric lines of force leave or enter the charge surface at an angle of
a)
30
b)
45
c)
90
d)
depending upon the angle of launch and entry
255.
Electric field intensity is measured in
a)
volts/meter
b)
Newton/meter
c)
Newton-meter
d)
Amperes/meter
256.
Electric field intensity is a ____________
a)
scalar
b)
phasor
c)
vector
d)
variable
257.
Electric field intensity at a point due to a given charge ___________ if the relative permittivity of the medium decreases
a)
decreases
b)
remains unchanged
c)
increases
d)
becomes zero
258.
The electric field intensity between the parallel plate air capacitor is 20 N/C. If an insulating slab of relative permittivity 5 is placed between the plates, then electric field intensity will be
a)
20 N/C
b)
100 N/C
c)
4 N/C
d)
40 N/C
259.
The electric flux density is a ___________ quantity
a)
phasor
b)
vector
c)
scalar
d)
variable
260.
The permittivity of a material is given by one of the following formulas
a)
DE
b)
E/D
c)
D^2/E
d)
D/E
261.
Electric field intensity at a point is numerically equal to ____________ at that point
a)
potential gradient
b)
potential difference
c)
dielectric constant
d)
the force
262.
Three charges of +5 C, -6 C and +9 C are placed inside a sphere. What is the total flux passing through the surface of sphere?
a)
8 C
b)
14 C
c)
20 C
d)
-6 C
263.
The potential at a point due to a charge is 15 V. If the distance is increased three times, the potential at the point will be
a)
5 V
b)
18 V
c)
45 V
d)
15 V
264.
Electric potential is a __________ quantity
a)
scalar
b)
phasor
c)
vector
d)
variable
265.
The electric potential at a point in air due to a charge is 21 V. If the air is replaced by a medium of relative permittivity of 3, then electric potential at that point will be
a)
63 V
b)
21 V
c)
7 V
d)
42 V
266.
The electric potential across part AB of a circuit is 5 V point A being at higher potential. If a charge of 5 C moves from A to B, then energy released as
a)
5 joules
b)
25 joules
c)
10 joules
d)
100 joules
267.
What is the other name for dielectric strength?
a)
Breakdown voltage
b)
Electric intensity
c)
Potential gradient
d)
Dielectric constant
268.
Which of the following materials has the highest dielectric strength?
a)
Glass
b)
Oiled paper
c)
Mica
d)
Air
269.
What is used as the insulating material or dielectric in an electric ion?
a)
Oiled paper
b)
Mica
c)
Paraffin
d)
Titanate compound
270.
What is used as the dielectric material in high voltage transformers?
a)
Mica
b)
Paraffin
c)
Porcelain
d)
Oiled paper
271.
One farad equals
a)
1 coulomb/volt
b)
1 newton/coulomb
c)
1 newton-meter
d)
1 volt/second/ampere
272.
Which of the following is used by permanent magnets as the magnetic material?
a)
iron
b)
nickel
c)
soft steel
d)
hardened steel
273.
Which of the following is used by temporary magnets as the magnetic material?
a)
Hardened steel
b)
Cobalt steel
c)
Soft iron
d)
Tungsten steel
274.
What is the main advantage of temporary magnets?
a)
The magnetic flux can be changed.
b)
Hysteresis can be decreased.
c)
Magnetic materials can be used.
d)
Abundance of ferromagnetic material that can be temporarily magnetized.
275.
Permanent magnets can be found in
a)
electric bells
b)
earphones
c)
relays
d)
dynamic loudspeakers
276.
Temporary magnets are commonly employed in
a)
electric instruments
b)
motors
c)
moving coils loudspeakers
d)
magnetos
277.
The force between two magnetic poles is ___________ their pole strengths
a)
directly proportional to
b)
the sum of
c)
inversely proportional to
d)
the product of
278.
If the distance between two magnetic poles decreases by 2 times, the force between them
a)
decreases two times
b)
increases four times
c)
increases two times
d)
decreases four times
279.
The force between two magnetic poles is ____________ the relative permeability of the medium
a)
directly proportional to
b)
independent of
c)
inversely proportional to
d)
equal to
280.
Two similar poles, each 1Wb, placed 1 m apart in air will experience a repulsive force of
a)
63000 N
b)
63 × 10^-3 N
c)
8 × 10^12 N
d)
796 kN
281.
One weber of flux is equal to ___________ magnetic lines of force
a)
10^6
b)
10^10
c)
4π × 10^7
d)
10^8
282.
The unit of flux density is
a)
Wb/m
b)
Tesla
c)
At/m
d)
N/Wb
283.
What is the typical saturation flux density for most magnetic materials?
a)
4 Wb/m^2
b)
5 Wb/m^2
c)
1 Wb/m^2
d)
2 Wb/m^2
284.
Magnetic field intensity is a ___________ quantity
a)
scalar
b)
phasor
c)
vector
d)
variable
285.
The force acting on a pole of 5 Wb is 25 N. What is the intensity of the magnetic field?
a)
5 N/Wb
b)
25 N/Wb
c)
125 N/Wb
d)
0.2 N/Wb
286.
The relative permeability of a magnetic material is 10^5. What is its permeability?
a)
4π × 10^5 H/m
b)
4π × 10^-12 H/m
c)
4π × 10^-2 H/m
d)
4π × 10^-7 H/m
287.
Which of the following has the highest permeability?
a)
Soft iron
b)
Steel
c)
Air
d)
Permalloy
288.
A magnetic pole produces 5000 field lines. How much is the flux in webers?
a)
50 × 10^-6
b)
5 × 10^-6
c)
500 × 10^-6
d)
500 × 10^-5
289.
As the magnetic intensity decreases, the relative permeability of a magnetic material
a)
decreases
b)
remains the same
c)
increases
d)
becomes zero
290.
The permeability of a material having a flux density of 5 Wb/m^2 is 10^-5 H/m. What is the value of magnetizing force?
a)
5 × 10^-5 N/Wb
b)
500 × 10^3 N/Wb
c)
4π × 10^-7 N/Wb
d)
4π × 10^7 N/Wb
291.
When the relative permeability of a material is slightly less than 1, it is called _________ material
a)
diamagnetic
b)
ferromagnetic
c)
paramagnetic
d)
non-magnetic
292.
When the relative permeability of a material is slightly more than 1, it is called _________ material
a)
diamagnetic
b)
ferromagnetic
c)
paramagnetic
d)
non-magnetic
293.
Which of the following is a diamagnetic material?
a)
Aluminum
b)
Silver
c)
Air
d)
Cobalt
294.
Which of the following is a paramagnetic material?
a)
Carbon
b)
Bismuth
c)
Copper
d)
Oxygen
295.
The greater percentage of materials is ____________
a)
diamagnetic
b)
paramagnetic
c)
ferromagnetic
d)
non-magnetic
296.
When the relative permeability of a material is much greater than 1, it is called __________ material
a)
diamagnetic
b)
ferromagnetic
c)
paramagnetic
d)
non-magnetic
297.
The flux density in an air-cored coil is 10^-3 Wb/m^2. With a cast iron core of relative permeability 100 inserted, the flux density will become
a)
10^-3 Wb/m^2
b)
10^-2 Wb/m^2
c)
10^3 Wb/m^2
d)
0.1 Wb/m^2
298.
At/m is a unit of
a)
mmf
b)
magnetic force
c)
reluctance
d)
magnetic flux density
299.
The direction of force o a current carrying conductor placed in a magnetic field can be found by
a)
Cork screw rule
b)
Fleming's left hand rule
c)
Fleming's right hand rule
d)
using a compass
300.
When a current carrying conductor is placed in a magnetic field, the maximum force will act on the conductor when the conductor is at an angle of ___________ to the magnetic field
a)
45
b)
60
c)
30
d)
90
301.
What composes all matter whether a liquid, solid, or gas?
a)
Atoms
b)
Electrons
c)
Protons
d)
Neutrons
302.
Which of the following is not a basic part of an atom?
a)
Electron
b)
Proton
c)
Neutron
d)
Coulomb
303.
What is the smallest element of a matter?
a)
atom
b)
molecule
c)
crystal
d)
wafer
304.
To determine whether a material can support the flow of electricity or not, we need to examine its
a)
atomic structure
b)
physical state
c)
molecular structure
d)
chemical composition
305.
Approximate diameter of an atom
a)
10^-10 µµm
b)
10^-10 µm
c)
10^-10 mm
d)
10^-10 m
306.
The lightest kind of atom or element
a)
Helium
b)
Oxygen
c)
Hydrogen
d)
Titanium
307.
Known as the simplest type of atom
a)
Hydrogen
b)
Oxygen
c)
Helium
d)
Nitrogen
308.
Approximate diameter of a Hydrogen atom
a)
1.1 x 10^-10 µµm
b)
1.1 x 10^-10 µm
c)
1.1 x 10^-10 mm
d)
1.1 x 10^-10 m
309.
A commonly used model in predicting the atomic structure of a material
a)
String model
b)
Wave model
c)
Particle model
d)
Bohr model
310.
Is at the center of an atomic structure in a Bohr model
a)
electrons
b)
protons
c)
neutrons
d)
nucleus
311.
The nucleus of an atom is normally
a)
neutral
b)
positively charged
c)
negatively charged
d)
either positively or negatively charged
312.
What particles that revolve around the positive nucleus?
a)
electrons
b)
protons
c)
neutrons
d)
electrons & protons
313.
In electricity, positive electric charge refers to ____________
a)
protons
b)
neutrons
c)
electrons
d)
atoms
314.
What is the charge of an electron?
a)
1.6022 x 10^-19 C
b)
9.1096 x 10^-19 C
c)
1.6022 x 10^-31 C
d)
9.1096 x 10^-31 C
315.
The mass of a proton is approximately
a)
1.6726 x 10^-19 Kg
b)
1.6726 x 10^-27 Kg
c)
1.6022 x 10^-19 Kg
d)
1.6022 x 10^-27 Kg
316.
Protons are about _________ heavier than electrons
a)
1,800 times
b)
less than thrice
c)
less
d)
twice
317.
Approximately, how many electrons that could equal to the mass of a single proton or neutron?
a)
1,863 electrons
b)
1,683 electrons
c)
1,638 electrons
d)
1,836 electrons
318.
The maximum number of electrons (Ne) that can occupy a given shell (n) is determined by the formula
a)
Ne = 2n^2
b)
Ne = n^2
c)
Ne = 2^n
d)
Ne = 2n
319.
The discrete amount of energy required to move an electron from a lower shell to a higher shell
a)
negative energy
b)
positive energy
c)
quantum
d)
quanta
320.
Maximum number of orbiting electrons at the first or K shell
a)
2
b)
4
c)
6
d)
8
321.
Electron is derived from the Greek name elektron which means
a)
huge
b)
tiny
c)
particle
d)
amber
322.
Electric charge of neutron is the same as
a)
proton
b)
electron
c)
current
d)
atom
323.
In an atomic structure, what particle that has no charge and therefore has no effect on its atomic charge
a)
electrons
b)
protons
c)
neutrons
d)
nucleons
324.
The atomic number of an element is determined by the number of
a)
electrons
b)
valence electrons
c)
protons
d)
protons or neutrons
325.
The atomic weight of an element is determined by the number of
a)
electrons
b)
valence electrons
c)
protons
d)
protons and neutrons
326.
If an element has an atomic number of 12, there are how many protons and electrons?
a)
6 protons and 12 electrons
b)
12 protons and 6 electrons
c)
12 protons and 12 electrons
d)
12 protons and 24 electrons
327.
Suppose there is an atom containing eight protons and eight neutrons in the nucleus, and two neutron are added to the nucleus, the resulting atomic weight is about
a)
8
b)
10
c)
16
d)
18
328.
It is composed of a series of energy levels containing the valence electrons
a)
conduction band
b)
forbidden band
c)
side band
d)
valence band
329.
Electrons at the conduction band are called
a)
free electrons
b)
valence electrons
c)
deep state electrons
d)
shallow state electrons
330.
_____________ are electrons at the outer shell
a)
Inside shell electrons
b)
Conductor electrons
c)
Outside shell electrons
d)
Valence electrons
331.
Electrons at the outermost shell are called
a)
free electrons
b)
valence electrons
c)
deep state electrons
d)
shallow state electrons
332.
Which material has more free electrons?
a)
Conductor
b)
insulators
c)
mica
d)
dielectric
333.
Which material has the least number of valence electrons?
a)
conductor
b)
semiconductor
c)
insulator
d)
semi-insulator
334.
What elements possess four valence electrons?
a)
Insulators
b)
Semi-insulators
c)
Semiconductors
d)
Conductors
335.
A good conductor has how many valence electrons?
a)
1
b)
2
c)
4
d)
8
336.
Materials that might have eight valence electrons
a)
conductor
b)
insulator
c)
semiconductor
d)
semi-insulator
337.
An insulating element or material has capability of _________
a)
conducting large current
b)
storing voltage
c)
storing high current
d)
preventing short circuit between two conducting wires
338.
A law of nature makes certain materials tend to form combinations that will make them stable. How many electrons in the valence orbit are needed to give stability?
a)
1
b)
2
c)
4
d)
8
339.
Determine which statement is true?
a)
The current carriers in conductors are protons.
b)
The current carriers in conductors are valence electrons.
c)
Valence and inner electrons are the carriers in conductors.
d)
Valence electrons are not the ones that become free electrons.
340.
A material that contains an abundance of free carrier is called
a)
insulator
b)
semi-insulator
c)
conductor
d)
semiconductor
341.
From the combined energy-gap diagram, which material has the widest gap between valence band and the conduction band?
a)
conductor
b)
semiconductor
c)
super conductor
d)
insulator <
342.
From the combined energy-gap diagram, which material has the smallest energy gap between valence band and the conduction band?
a)
conductor
b)
semiconductor
c)
super conductor
d)
insulator
343.
__________ has a unit of electronvolt(eV)
a)
Charge
b)
Potential difference
c)
Energy
d)
Current
344.
The difference in energy between the valence and conduction bands of a semiconductor is called
a)
band gap
b)
extrinsict photoeffect
c)
conductivity
d)
energy density
345.
The energy gap between the valence band and conduction band of a conductor is in the order of
a)
zero electron volt (0 eV)
b)
one electron volt (1 eV)
c)
five electron volt (5 eV)
d)
ten electron volt (10 eV)
346.
The energy gap of an insulator is in the order of
a)
zero electron volt (0 eV)
b)
one electron volt (1 eV)
c)
five electron volt (5 eV)
d)
one-tenth electron volt (0.1 eV)
347.
In materials, what do you call the region that separates the valence and conduction bands?
a)
energy gap
b)
forbidden band
c)
insulation band
d)
energy gap or forbidden band
348.
What do you call the potential required to remove a valence electron?
a)
valence potential
b)
threshold potential
c)
critical potential
d)
ionization potential
349.
A factor that does not affect the resistance of the material
a)
atomic structure
b)
mass
c)
length
d)
cross-sectional area
350.
Copper atom has how many protons?
a)
1
b)
4
c)
8
d)
29
351.
Ion is __________
a)
an atom with unbalanced charges
b)
free electron
c)
proton
d)
nucleus without protons
352.
What will happen to an atom if an electron is either taken out or taken into the same atom?
a)
Becomes negative ion
b)
Becomes positive ion
c)
Becomes an ion
d)
Nothing will happen
353.
When an atom gains an additional _________, it results to a negative ion
a)
neutron
b)
proton
c)
electron
d)
atom
354.
An electrical insulator can be made a conductor by
a)
ionizing
b)
electroplating
c)
oxidizing
d)
metalization
355.
Refers to the lowest voltage across any insulator that can cause current flow
a)
conduction voltage
b)
breakdown voltage
c)
voltage flow
d)
voltage drop
356.
Dielectric is another name for
a)
conductor
b)
semiconductor
c)
insulator
d)
semi-insulator
357.
When all atoms of a molecule are the same, the substance is called
a)
a crystal
b)
an element
c)
a compound
d)
an ion
358.
An isotope
a)
has a negative charge
b)
has a positive charge
c)
might have either positive or negative charge
d)
is neutral
359.
Isotope means, the same element but with different number of
a)
electrons
b)
neutrons
c)
protons
d)
atoms
360.
The particles that make up the lattice in ionic crystal
a)
molecules
b)
ions
c)
electrons
d)
neutrons
361.
A structure for solids in which the position of atoms are predetermined
a)
Crystalline
b)
Polycrystalline
c)
Lattice
d)
Non-Crystalline
362.
A solid, which has no defined crystal structure
a)
Crystalline
b)
Non-crystalline
c)
Amorphous
d)
Non-crystalline or Amorphous
363.
States that each electron in an atom must have a different set of quantum numbers
a)
Quantum principle
b)
Fermi-Dirac principle
c)
Spin principle
d)
Exclusion principle
364.
Given an atomic structure of a certain material, what data can you determine out from it?
a)
atomic number
b)
atomic mass
c)
the number of protons and electrons
d)
all of the above
365.
Ideally, all atoms have the same number of positively charged protons and negatively charged electrons, and is therefore considered as
a)
electrically neutral
b)
physically stable
c)
magnetically aligned
d)
technically rigid
366.
When the charge of an atom becomes unbalanced, the atom is said to carry
a)
Electric charge
b)
Magnetic charge
c)
Electromagnetic charge
d)
Electrical current
367.
A charged atom is also known as
a)
ion
b)
anion
c)
cation
d)
domain
368.
An atom or group of atoms that carries a net electric charge is called
a)
ion
b)
anion
c)
cation
d)
domain
369.
A negative ion results when an atom
a)
loss some of its inside electrons
b)
loss some of its valence electrons
c)
gains additional electron
d)
gains additional proton
370.
A positive ion has
a)
excess of electrons
b)
excess of neutrons
c)
lack of electrons
d)
lack of protons
371.
What do you call a positively charged ion?
a)
cathode
b)
anion
c)
cation
d)
domain
372.
What do you call a negatively charged ion?
a)
electron
b)
anion
c)
cation
d)
domain
373.
__________ is the procedure by which an atom is given a net charge by adding or taking away electron
a)
Polarization
b)
Irradiation
c)
Ionization
d)
Doping
374.
Is a process by which an atom is constantly losing and then regaining electrons?
a)
oxidation
b)
passivation
c)
metallization
d)
ionization
375.
The process in which atoms are changed into ions
a)
oxidation
b)
passivation
c)
metallization
d)
ionization
376.
Gases with charged particles
a)
inert
b)
plasma
c)
conductive
d)
reactive
377.
One Coulomb of charge has how many electrons?
a)
6.24 x 10^18 electrons
b)
6.24 x 10^19 electrons
c)
62.4 x 10^18 electrons
d)
62.4 x 10^19 electrons
378.
Coulomb is the SI unit of charge, how about in cgs?
a)
Statcoulomb
b)
electron volt
c)
electron unit
d)
static unit
379.
Statcoulomb is also known as
a)
electrostatic unit (esu)
b)
electron volt
c)
electron unit
d)
static unit
380.
An isolated body under normal condition is always
a)
neutral
b)
positively charged
c)
negatively charged
d)
ionized
381.
What is the charge magnitude, Q of a body if it lacks 5 electrons?
a)
5 x 10^-19 Coulomb
b)
5 Coulomb
c)
8 x 10^-19 Coulomb
d)
19 x 10^-19 Coulomb
382.
The net movement of charged particles in one direction or another
a)
flow
b)
current
c)
drift current
d)
diffusion current
383.
The rate at which electrons pass a given point in the circuit gives the magnitude of
a)
electron current
b)
magnetic current
c)
drift current
d)
diffusion current
384.
The unit of current
a)
Ampere
b)
Ampere/sec.
c)
Ampere-sec.
d)
Ampere-hr.
385.
The unit Ampere is equivalent to
a)
one Coulomb/second
b)
one Coulomb/min
c)
one Joule/sec
d)
one Joule/min
386.
When one coulomb of electric charge continuously passes a given point every second, the electric current is said to
a)
1 µA
b)
1 mA
c)
01:00:00
d)
10:00:00
387.
One ampere is equal to how many electrons per second?
a)
1 x 10^18 electrons/sec.
b)
1 x 10^19 electrons/sec.
c)
6.25 x 10^18 electrons/sec.
d)
6.25 x 10^19 electrons/sec.
388.
The bigger the diameter of a wire,
a)
more current can pass
b)
less current can pass
c)
more heat is generated when current flow
d)
the higher is the electrical resistance
389.
If in a material, current can hardly pass, it means
a)
the material is very hard
b)
the material is very soft
c)
the material has high resistance
d)
the material has less resistance
390.
The greater the diameter of a wire, the _______ is the resistance
a)
greater
b)
lesser
c)
harder
d)
bigger
391.
The longer the wire the ________ is the resistance
a)
higher
b)
lesser
c)
harder
d)
smaller
392.
If a conductor's cross-sectional area is doubled and its length is halved, the value of its resistance will
a)
double
b)
quadruple
c)
decrease by a factor of two
d)
decrease by a factor of four
393.
The amount of resistance that a wire has with regards to the flow of electric current
a)
is less for a conductor than for an insulator
b)
is less for an insulator than for a semiconductor
c)
is less for a semiconductor than for a conductor
d)
is high for a semiconductor than for an insulator
394.
The area of a conductor whose diameter is 0.001 inch is equal to
a)
one angstrom
b)
one circular mil
c)
one micron
d)
one steradian
395.
A 100m long wire with a cross-sectional area A=10-3 m2 has a resistance of 10Ω. Determine the resistivity of the wire
a)
10^-2 Ω-m
b)
10^-3 Ω-m
c)
10^-4 Ω-m
d)
10^-5 Ω-m
396.
the reciprocal of resistance
a)
permeance
b)
elastance
c)
inductance
d)
conductance
397.
The science of physical phenomena at very low temperature, approaching absolute zero is called ________
a)
cryptanalysis
b)
cybernetics
c)
temperature inversion
d)
cryogenics
398.
What happens in the resistance of copper wire when its temperature is raised?
a)
decreased
b)
steady
c)
increased
d)
zero
399.
A wire has a resistance of 5Ω at room temperature and a temperature coefficient α = 4 x 10^-3/°C, calculate the wire resistance at 75° C
a)
8.925 Ω
b)
7.925 Ω
c)
6.925 Ω
d)
6.050 Ω
400.
The temperature coefficient of resistance of a certain wire is known to be 0.004/°C at zero degrees Celsius
a)
0.00018/°C
b)
0.00036/°C
c)
0.00180/°C
d)
0.00360/°C
401.
Where does practically all of the RF current flow in a conductor?
a)
along the surface
b)
in the center of the conductor
c)
in the electromagnetic field in the conductor center
d)
in the magnetic field around the conductor
402.
________ is one factor that does not affect resistance
a)
Cross sectional area
b)
Resistivity
c)
Mass
d)
Length
403.
Why is the resistance of a conductor different for RF current than for DC?
a)
Because of skin effect
b)
Because conductors are non-linear devices
c)
Because the insulation conducts current at radio frequency
d)
Because of the Heisenberg effect
404.
The ability of a material to resist current flow is called "resistance". What is (are) the factor(s) that affect its value?
a)
temperature
b)
length & cross-sectional area
c)
atomic structure
d)
all of these
405.
Find the charge in coulombs of dielectric that has a positive charge of 14.5 x 10 to the 18th power protons
a)
29 x 10 to the 16th Coulombs
b)
14.5 x 10 to the 16th Coulombs
c)
14.5 x 10 to the 18th Coulombs
d)
29 x 10 to the 18th Coulombs
406.
Electron volt (eV) is a unit of
a)
power
b)
energy
c)
magnetic field
d)
magnetic force
407.
One electron volt (eV) is equivalent to
a)
1.0 watt-sec
b)
1.6 x 10^-19 watt-sec
c)
1.0 Joule
d)
1.6 x 10^-19 Joules
408.
What law that describes the force of attraction or repulsion between two charges is directly proportional to their strengths and inversely proportional to the square of the distance between them?
a)
Coulomb's first law
b)
Coulomb's second law
c)
Coulomb's third law
d)
Coulomb's law or law of electrostatics
409.
What is the law whereby the force of attraction and repulsion between poles is inversely proportional to the square of the distance between them?
a)
Newton's first law
b)
Newton's second law
c)
Norton's law
d)
Coulomb's second law
410.
Is usually used to detect the presence of electric charge
a)
experimental charge
b)
unit charge
c)
dipole
d)
test charge
411.
Test charge has a charge of
a)
0 Coulomb
b)
+1 Coulomb
c)
-1 Coulomb
d)
Infinity
412.
Three charges of +5 C, -6 C and +7 C are placed inside a sphere, what is the total charge of the sphere?
a)
+5 Coulomb
b)
-6 Coulomb
c)
-7 Coulomb
d)
+6 Coulomb
413.
A combination of two charges, with equal charge magnitude but opposite signs
a)
magnetic dipole
b)
static dipole
c)
dynamic dipole
d)
electric dipole
414.
The space outside or surrounding an electric charge where it has a force of attraction or repulsion
a)
Electric field
b)
Magnetic field
c)
Electromagnetic field
d)
Electric flux
415.
Refers to a force of field that exists between ions where they either repel or attract each other
a)
Resisting field
b)
Potential field
c)
Dielectric
d)
Electromotive
416.
The imaginary lines representing the electric field
a)
Electric field
b)
Electric flux
c)
Electric flux density
d)
Electric lines of force
417.
What is true in visualizing electric field lines of force from a charge body?
a)
Field lines are continuous curve and they never intersect.
b)
The spacing between these lines increases as they get far from the charged body.
c)
The number of field lines is directly proportional to the magnitude of the electric field.
d)
All of the above.
418.
What do you call the total number of electric lines of force in an electric field?
a)
Electric field
b)
Electric flux
c)
Electric flux density
d)
Electric lines of force
419.
The number of lines per unit area in a plane perpendicular to the electric lines of force
a)
Electric field
b)
Electric flux
c)
Electric flux density
d)
Electric lines of force
420.
Electric lines of force leave and enter the charge surface at what angle?
a)
15°
b)
30°
c)
45°
d)
90°
421.
Find the dielectric constant of air
a)
approximately 1
b)
approximately 0
c)
approximately 2
d)
approximately 4
422.
Electric field intensity is measured in terms of
a)
Volts/meter
b)
Newtons/meter
c)
Watts/meter
d)
Amperes/meter
423.
Electric field intensity is
a)
a scalar quantity
b)
a vector quantity
c)
an absolute value
d)
a relative value
424.
Electric flux is a/an ________ quantity
a)
scalar
b)
vector
c)
absolute
d)
relative
425.
Electric flux density is a/an ________ quantity
a)
scalar
b)
vector
c)
absolute
d)
relative
426.
Three charges of +5 C, -6 C, and +7 C are inside a sphere, what is the total electric flux passing through the surface of the sphere?
a)
5 Coulombs
b)
6 Coulombs
c)
7 Coulombs
d)
8 Coulombs
427.
An electric charge produces a total electric field of 6 Coulombs, calculate the electric flux density in an area of one square meter (1m2)
a)
1 C/m^2
b)
2 C/m^2
c)
4 C/m^2
d)
6 C/m^2
428.
The measure of density of the electric charge
a)
Electric gradient
b)
Electric current
c)
Electric charge
d)
Electric potential
429.
The ability of the material to store electrical potential energy under the influence of an electric field
a)
capacity
b)
permeability
c)
permittivity
d)
conductivity
430.
The absolute permittivity of air or free space
a)
1/36π x 10^-9 F/m
b)
36π x 10^-9 F/m
c)
1/36π x 10^-19 F/m
d)
36π x 10^-19 F/m
431.
The relative permittivity of air
a)
0
b)
1
c)
1/36π x 10^-9 F/m
d)
8.854 x 10^-12 F/m
432.
Calculate the permittivity of a material with relative permittivity of 5
a)
8.854 x 10^-11 F/m
b)
4.42 x 10^-11 F/m
c)
1/36π x 10^-9 F/m
d)
8.854 x 10^-12 F/m
433.
What is the term used to express the amount of electrical energy stored in an electrostatic field?
a)
Volts
b)
Watts
c)
Coulombs
d)
Joules
434.
How does permittivity affect electric field intensity?
a)
It causes the field intensity to increase.
b)
It causes the field intensity to decrease.
c)
It causes the field intensity to fluctuate up and down.
d)
It has no effect on field intensity.
435.
Relative permittivity is also known as
a)
dielectric constant
b)
dielectric strength
c)
isolation strength
d)
permeability
436.
Most materials' relative permittivity lies between
a)
0.01 - 1
b)
2023-01-10 00:00:00
c)
1950-10-01 00:00:00
d)
50 - 100
437.
Charge body at rest is said to exhibit electric field, which interacts with other bodies. The study of this phenomena is known as
a)
electricity
b)
electrostatics
c)
electromagnetism
d)
field interactions
438.
The basic law for interaction of charged bodies at rest
a)
Charged law
b)
Gauss' law
c)
Faraday's law
d)
Coulomb's law
439.
The force between the two electrically charged body is called
a)
electromotive force
b)
electrostatic force
c)
electromagnetic force
d)
magnetic force
440.
The force between two electrically charged body is
a)
directly proportional to the charge
b)
inversely proportional to the charge
c)
not affected by the charge
d)
universally constant
441.
In 1784, who demonstrated that the force between charges is inversely related to the square of the distance between them?
a)
Maxwell
b)
Gauss
c)
Tesla
d)
Coulomb
442.
Determine the force in Newton between 4μC charges separated by 0.1 meter in air
a)
1.44 N
b)
14.4 N
c)
144 N
d)
1440 N
443.
What will happen when two opposite charges get closer?
a)
repels less
b)
attracts less
c)
repels more
d)
attracts more
444.
The value of k in Coulomb's electrostatic force equation ( F = kQ1Q2/r^2 ) is oftentimes expressed as 1/4πεο. What is εο?
a)
absolute permeability
b)
absolute permittivity
c)
relative permeability
d)
relative permittivity
445.
The measure of electric field strength per unit length is known as electric field intensity or simply electric intensity. What is its unit?
a)
Volt/meter (V/m)
b)
Joules/Coulomb-meter (J/Cm)
c)
Newton/Coulomb (N/C)
d)
All of the above
446.
Calculate the electric field intensity 10cm from a charge Q = 5nC
a)
450 N/C
b)
900 N/C
c)
4.5 x 10^3 N/C
d)
9.0 x 10^3 N/C
447.
Determine the magnitude of the electric field inside a sphere that encloses a net charge of 2 μC
a)
0 (zero)
b)
9 x 10^7 N/C
c)
1.8 x 10^8 N/C
d)
infinite
448.
Calculate the total electric field at the surface of a sphere of radius r = 1cm, and enclosing a net charge of 2 μC
a)
0 (zero)
b)
9 x 10^7 N/C
c)
1.8 x 10^8 N/C
d)
infinite
449.
A 2nC point charge will produce what potential at 2 m away?
a)
4.0 Volts
b)
6.0 Volts
c)
7.5 Volts
d)
9.0 Volts
450.
A charged body in free space produces 10-V potential at a distance 25 cm away. What will be the potential at 50 cm away?
a)
5.0 Volts
b)
7.5 Volts
c)
10.0 Volts
d)
15.0 Volts
451.
What do you call the phenomenon whereby substance attracts pieces of iron?
a)
Permeability
b)
Magnetism
c)
Naturalism
d)
Electromagnetism
452.
The condition in which a substance attracts pieces of iron is known as
a)
Electromagnetism
b)
Electrolysis
c)
Magnetism
d)
Magnetic Induction
453.
A substance that attracts pieces iron is known as
a)
magnet
b)
conductor
c)
ferrite
d)
superconductor
454.
A natural magnet
a)
loadstone
b)
carbon
c)
lodestone
d)
magnesium
455.
Group of magnetically aligned atoms
a)
Lattice
b)
Crystal
c)
Domain
d)
Range
456.
In a magnet, what do you call the point in which the magnetic lines of force is maximum?
a)
maximum pole
b)
intensified pole
c)
unit pole
d)
magnetic pole
457.
Which of the following refers to a characteristic of a magnetic line of force?
a)
Travels from south to north through the surrounding medium of a bar magnet
b)
Travels back and forth between the north and south pole of a bar magnet
c)
Travels from north to south through the surrounding medium of a bar magnet
d)
Stay stationary between the north and the south of a bar magnet
458.
Is believed to be the pole where the magnetic lines of force are originating
a)
North Pole
b)
South Pole
c)
Unit Pole
d)
Universal Pole
459.
What do you call a pole that when place in air with a similar and equal pole will cause a force of repulsion of 1/4πμο Newtons?
a)
South Pole
b)
Unit pole
c)
Convergence pole
d)
Universal Pole
460.
In a magnet, the straight line passing through the two poles is called
a)
real axis
b)
imaginary axis
c)
Cartesian axis
d)
magnetic axis
461.
The phenomenon in which a substance becomes a magnet when placed near a magnet
a)
magnetic transfer
b)
magnetic induction
c)
electromagnetism
d)
magnetism
462.
A force which causes a substance to become a magnet
a)
magnetizing force
b)
magnetomotive
c)
creative force
d)
electromagnetic force
463.
What do you call the quantity of magnetism retained by a magnetic material after the withdrawal of a magnetizing force?
a)
Left over magnetism
b)
Coercivity
c)
Hysteresis
d)
Residual magnetism
464.
Is the property of magnetic materials, which retain magnetism after the withdrawal of magnetizing force
a)
retentivity
b)
permeability
c)
reluctivity
d)
susceptability
465.
A substance having high retentivity is best suited in making
a)
an electromagnet
b)
a temporary magnet
c)
a permanent magnet
d)
two pole magnet
466.
Which of the materials below that can be easily magnetized?
a)
soft magnetic materials
b)
hard magnetic materials
c)
low conductive materials
d)
high conductive materials
467.
Materials that can be easily magnetized in both directions
a)
soft magnetic materials
b)
hard magnetic materials
c)
diamagnetic
d)
paramagnetic
468.
Ability of a material to conduct magnetic flux through it refers to
a)
permittivity
b)
permeability
c)
reluctivity
d)
conductivity
469.
The ability to concentrate magnetic lines of force
a)
retentivity
b)
permeability
c)
susceptability
d)
reluctivity
470.
The permeability of free space
a)
4π x 10^-7 H/m
b)
12.56 x 10^-7 F/m
c)
8.854 x 10^-7 H/m
d)
8.854 x 10^-12 F/m
471.
The ratio of material permeability to the permeability of air or vacuum
a)
relative conductivity
b)
relative permeability
c)
inverse permeability
d)
inverse permittivity
472.
What is the relative permeability of air?
a)
0
b)
1
c)
4π x 10^-7 H/m
d)
8.854 x 10^-12 F/m
473.
Materials with permeability slightly less than that of free space
a)
diamagnetic
b)
paramagnetic
c)
ferromagnetic
d)
antimagnetic
474.
Materials with permeability slightly greater than that of free space
a)
diamagnetic
b)
paramagnetic
c)
ferromagnetic
d)
antimagnetic
475.
What do you call materials, which possess very high permeabilities?
a)
diamagnetic
b)
paramagnetic
c)
ferromagnetic
d)
antimagnetic
476.
What is the relative permeability of paramagnetic substance?
a)
slightly greater than 1
b)
very much greater than 1
c)
slightly less than 1
d)
very much smaller than 1
477.
Permeability of a material means:
a)
The ability of the material to conduct electric field
b)
The conductivity of the material for electromagnetic field
c)
The ability of the material to hold magnetic flux
d)
The conductivity of the material for magnetic lines of force
478.
Nonmetallic materials that has ferromagnetic properties
a)
termites
b)
ferrites
c)
ferrous
d)
loadstone
479.
Cores of magnetic equipment use magnetic material which has
a)
very low permeability
b)
moderate permeability
c)
low permeability
d)
high permeability
480.
Hydrogen is an example of a _________ material
a)
diamagnetic
b)
ferromagnetic
c)
paramagnetic
d)
magnetic
481.
Cobalt is an example of a _________ material
a)
diamagnetic
b)
ferromagnetic
c)
paramagnetic
d)
magnetic
482.
The space outside a magnet where its poles has a force of attraction or repulsion on another magnetic pole
a)
magnetic field
b)
magnetic flux
c)
magnetic flux density
d)
magnetic lines of force
483.
The imaginary lines representing the magnetic field
a)
magnetic field
b)
magnetic flux
c)
magnetic flux density
d)
magnetic lines of force
484.
What do you call the total number of magnetic lines of force in a magnetic field?
a)
magnetic field
b)
magnetic flux
c)
magnetic flux density
d)
magnetic lines of force
485.
The number of lines per unit area in a plane perpendicular to the magnetic lines of force
a)
magnetic field
b)
magnetic flux
c)
magnetic flux density
d)
magnetic lines of force
486.
The direction of field lines outside a magnet is
a)
from north to south pole
b)
from south to north pole
c)
either from north to south or south to north pole
d)
dependent on the magnet's orientation with respect to the earth's magnetic pole
487.
The entire group of magnetic field lines flowing outward from the north pole of a magnet
a)
magnetic field
b)
magnetic flux density
c)
magnetic flux
d)
electromagnetic field
488.
Magnetic lines of force are called
a)
magnetic field
b)
magnetic flux density
c)
magnetic flux
d)
electromagnetic field
489.
What is the unit of magnetic flux in SI system?
a)
Weber
b)
Maxwell
c)
Tesla
d)
Gauss
490.
The unit of magnetic flux density in SI:
a)
Gauss
b)
Weber
c)
Maxwell
d)
Tesla
491.
A magnetic flux of 25,000 Maxwell in an area of 5 sq. cm. results in flux density of
a)
5,000 Gauss (G)
b)
125,000 G
c)
5,000 Tesla (T)
d)
125,000 T
492.
Calculate the flux density in Gauss (G) having a flux of 12,000 Mx through a perpendicular area of 6cm
a)
200 G
b)
2,000 G
c)
7,200 G
d)
72,000 G
493.
What does a gauss meter measure?
a)
flux
b)
magnetic field
c)
magnetic flux density
d)
mmf
494.
The capacity of a substance to become magnetized
a)
magnetic conductivity
b)
magnetic susceptibility
c)
magnetic resistivity
d)
magnetic reluctivity
495.
The typical saturation flux density for most magnetic materials
a)
0.1 Wb/m^2
b)
2 Wb/m^2
c)
10 Wb/m^2
d)
20 Wb/m^2
496.
The force between two magnetic poles is _________ permeability of the medium
a)
directly proportional to the
b)
inversely proportional to the
c)
not dependent of the
d)
exponentially proportional to the
497.
If the distance between two magnetic poles is halve, the force between them
a)
decreases two times
b)
decreases four times
c)
increases two times
d)
increases four times
498.
A force of 20 N is acting on a 10 Wb magnetic pole, calculate the intensity of the magnetic field?
a)
0.5 N/Wb
b)
2 N/Wb
c)
10 N/Wb
d)
20 N/Wb
499.
Unit of permeability
a)
Henry/meter (H/m)
b)
Farad/meter (F/m)
c)
Henry-meter (H-m)
d)
Farad-meter (F-m)
500.
The unit of permittivity
a)
Henry/meter (H/m)
b)
Farad/meter (F/m)
c)
Henry-meter (H-m)
d)
Farad-meter (F-m)
100 %