Test 1 Flashcards
(270 cards)
1
Q
What composes all matter whether a liquid, solid, or gas?
A. Atoms
B. Electrons
C. Protons
D. Neutrons
A
A. Atoms
2
Q
Which of the following is not a basic part of an atom?
A. Electron
B. Proton
C. Neutron
D. Coulomb
A
D. Coulomb
3
Q
What is the smallest element of a matter?
A. atom
B. molecule
C. crystal
D. wafer
A
A. atom
4
Q
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
A
A. atomic structure
5
Q
Approximate diameter of an atom
A. 10-10 µµm
B. 10-10 µm
C. 10-10 mm
D. 10-10 m
A
D. 10-10 m
6
Q
The lightest kind of atom or element
A. Helium
B. Oxygen
C. Hydrogen
D. Titanium
A
C. Hydrogen
7
Q
Known as the simplest type of atom.
A. Hydrogen
B. Oxygen
C. Helium
D. Nitrogen
A
A. Hydrogen
8
Q
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
A
B. 1.1 x 10-10 µm
9
Q
A commonly used model in predicting the atomic structure of a material.
A. String model
B. Wave model
C. Particle model
D. Bohr model
A
D. Bohr model
10
Q
Is at the center of an atomic structure in a Bohr model.
A. electrons
B. protons
C. neutrons
D. nucleus
A
D. nucleus
11
Q
The nucleus of an atom is normally
A. neutral
B. positively charged
C. negatively charged
D. either positively or negatively charged
A
A. neutral
12
Q
What particles that revolve around the positive nucleus?
A. electrons
B. protons
C. neutrons
D. electrons & protons
A
A. electrons
13
Q
In electricity, positive electric charge refers to ____________.
A. protons
B. neutrons
C. electrons
D. atoms
A
A. protons
14
Q
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
A
A. 1.6022 x 10-19 C
15
Q
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
A
B. 1.6726 x 10-27 Kg
16
Q
Protons are about _________ heavier than electrons.
A. 1,800 times
B. less than thrice
C. less
D. twice
A
A. 1,800 times
17
Q
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
A
D. 1,836 electrons
18
Q
The maximum number of electrons (Ne) that can occupy a given shell (n) is determined by the formula
A. Ne = 2n2
B. Ne = n2
C. Ne = 2n
D. Ne = 2n
A
A. Ne = 2n2
19
Q
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
A
C. quantum
20
Q
Maximum number of orbiting electrons at the first or K shell
A. 2
B. 4
C. 6
D. 8
A
A. 2
21
Q
Electron is derived from the Greek name elektron which means
A. huge
B. tiny
C. particle
D. amber
A
D. amber
22
Q
Electric charge of neutron is the same as
A. proton
B. electron
C. current
D. atom
A
D. atom
23
Q
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
A
C. neutrons
24
Q
The atomic number of an element is determined by the number of
A. electrons
B. valence electrons
C. protons
D. protons or neutrons
A
C. protons
25
The atomic weight of an element is determined by the number of
A. electrons
B. valence electrons
C. protons
D. protons and neutrons
D. protons and neutrons
26
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
C. 12 protons and 12 electrons
27
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
D. 18
28
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
D. valence band
29
Electrons at the conduction band are called
A. free electrons
B. valence electrons
C. deep state electrons
D. shallow state electrons
A. free electrons
30
_____________ are electrons at the outer shell
A. Inside shell electrons
B. Conductor electrons
C. Outside shell electrons
D. Valence electrons
D. Valence electrons
31
Electrons at the outermost shell are called
A. free electrons
B. valence electrons
C. deep state electrons
D. shallow state electrons
B. valence electrons
32
Which material has more free electrons?
A. Conductor
B. insulators
C. mica
D. dielectric
A. Conductor
33
Which material has the least number of valence electrons?
A. conductor
B. semiconductor
C. insulator
D. semi-insulator
A. conductor
34
What elements possess four valence electrons?
A. Insulators
B. Semi-insulators
C. Semiconductors
D. Conductors
C. Semiconductors
35
A good conductor has how many valence electrons?
A.1
B. 2
C. 4
D. 8
A.1
36
Materials that might have eight valence electrons
A. conductor
B. insulator
C. semiconductor
D. semi-insulator
B. insulator
37
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
D. preventing short circuit between two conducting wires
38
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
D. 8
39
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.
B. The current carriers in conductors are valence electrons.
40
A material that contains an abundance of free carrier is called
A. insulator
B. semi-insulator
C. conductor
D. semiconductor
C. conductor
41
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
D. insulator
42
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
A. conductor
43
__________ has a unit of electronvolt(eV).
A. Charge
B. Potential difference
C. Energy
D. Current
C. Energy
44
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
A. band gap
45
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)
A. zero electron volt (0 eV)
46
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)
C. five electron volt (5 eV)
47
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
D. energy gap or forbidden band
48
What do you call the potential required to remove a valence electron?
A. valence potential
B. threshold potential
C. critical potential
D. ionization potential
D. ionization potential
49
A factor that does not affect the resistance of the material.
A. atomic structure
B. mass
C. length
D. cross-sectional area
B. mass
50
Copper atom has how many protons?
A. 1
B. 4
C. 8
D. 29
D. 29
51
Ion is __________.
A. an atom with unbalanced charges
B. free electron
C. proton
D. nucleus without protons
A. an atom with unbalanced charges
52
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
C. Becomes an ion
53
When an atom gains an additional _________, it results to a negative ion.
A. neutron
B. proton
C. electron
D. atom
C. electron
54
An electrical insulator can be made a conductor by
A. ionizing
B. electroplating
C. oxidizing
D. metalization
A. ionizing
55
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
B. breakdown voltage
56
Dielectric is another name for
A. conductor
B. semiconductor
C. insulator
D. semi-insulator
C. insulator
57
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
B. an element
58
An isotope
A. has a negative charge
B. has a positive charge
C. might have either positive or negative charge
D. is neutral
D. is neutral
59
Isotope means, the same element but with different number of
A. electrons
B. neutrons
C. protons
D. atoms
B. neutrons
60
The particles that make up the lattice in ionic crystal
A. molecules
B. ions
C. electrons
D. neutrons
C. electrons
61
A structure for solids in which the position of atoms are predetermined
A. Crystalline
B. Polycrystalline
C. Lattice
D. Non-Crystalline
A. Crystalline
62
A solid, which has no defined crystal structure.
A. Crystalline
B. Non-crystalline
C. Amorphous
D. Non-crystalline or Amorphous
D. Non-crystalline or Amorphous
63
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
D. Exclusion principle
64
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
D. all of the above
65
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
A. electrically neutral
66
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
A. Electric charge
67
A charged atom is also known as
A. ion
B. anion
C. cation
D. domain
A. ion
68
An atom or group of atoms that carries a net electric charge is called
A. ion
B. anion
C. cation
D. domain
A. ion
69
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
C. gains additional electron
70
A positive ion has
A. excess of electrons
B. excess of neutrons
C. lack of electrons
D. lack of protons
C. lack of electrons
71
What do you call a positively charged ion?
A. cathode
B. anion
C. cation
D. domain
C. cation
72
What do you call a negatively charged ion?
A. electron
B. anion
C. cation
D. domain
B. anion
73
__________ 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
C. Ionization
74
Is a process by which an atom is constantly losing and then regaining electrons?
A. oxidation
B. passivation
C. metallization
D. ionization
D. ionization
75
The process in which atoms are changed into ions.
A. oxidation
B. passivation
C. metallization
D. ionization
D. ionization
76
Gases with charged particles.
A. inert
B. plasma
C. conductive
D. reactive
B. plasma
77
One Coulomb of charge has how many electrons?
A. 6.24 x 1018 electrons
B. 6.24 x 1019 electrons
C. 62.4 x 1018 electrons
D. 62.4 x 1019 electrons
A. 6.24 x 1018 electrons
78
Coulomb is the SI unit of charge, how about in cgs?
A. Statcoulomb
B. electron volt
C. electron unit
D. static unit
A. Statcoulomb
79
Statcoulomb is also known as
A. electrostatic unit (esu)
B. electron volt
C. electron unit
D. static unit
A. electrostatic unit (esu)
80
An isolated body under normal condition is always
A. neutral
B. positively charged
C. negatively charged
D. ionized
A. neutral
81
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
C. 8 x 10-19 Coulomb
82
The net movement of charged particles in one direction or another.
A. flow
B. current
C. drift current
D. diffusion current
B. current
83
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
A. electron current
84
The unit of current.
A. Ampere
B. Ampere/sec.
C. Ampere-sec.
D. Ampere-hr.
A. Ampere
85
The unit Ampere is equivalent to
A. one Coulomb/second
B. one Coulomb/min
C. one Joule/sec
D. one Joule/min
A. one Coulomb/second
86
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. 1 A
D. 10 A
C. 1 A
87
One ampere is equal to how many electrons per second?
A. 1 x 1018 electrons/sec.
B. 1 x 1019 electrons/sec.
C. 6.25 x 1018 electrons/sec.
D. 6.25 x 1019 electrons/sec.
D. 6.25 x 1019 electrons/sec.
88
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
A. more current can pass
89
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
C. the material has high resistance
90
The greater the diameter of a wire, the _______ is the resistance.
A. greater
B. lesser
C. harder
D. bigger
B. lesser
91
The longer the wire the ________ is the resistance
A. higher
B. lesser
C. harder
D. smaller
A. higher
92
If a conductors 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
D. decrease by a factor of four
93
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
A. is less for a conductor than for an insulator
94
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
B. one circular mil
95
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
C. 10-4 Ω-m
96
the reciprocal of resistance
A. permeance
B. elastance
C. inductance
D. conductance
D. conductance
97
The science of physical phenomena at very low temperature, approaching absolute zero is called ________.
A. crytanalysis
B. cybernetics
C. temperature inversion
D. cryogenics
D. cryogenics
98
What happens in the resistance of copper wire when its temperature is raised?
A. decreased
B. steady
C. increased
D. zero
C. increased
99
A wire has a resistance of 5Ω at room temperature and a temperature coefficient α=4x10-3/°C, calculate the wire resistance at 75°C.
A. 8.925 Ω
B. 7.925 Ω
C. 6.925 Ω
D. 6.050 Ω
D. 6.050 Ω
100
The temperature coefficient of resistance of a certain wire is known to be 0.004/°C at zero degrees Celsius. What would be the temperature coefficient at room temperature?
A. 0.00018/°C
B. 0.00036/°C
C. 0.00180/°C
D. 0.00360/°C
D. 0.00360/°C
101
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
A. along the surface
102
________ is one factor that does not affect resistance.
A. Cross sectional area
B. Resistivity
C. Mass
D. Length
C. Mass
103
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
A. Because of skin effect
104
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
D. all of these
105
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
C. 14.5 x 10 to the 18th Coulombs
106
Electron volt (eV) is a unit of
A. power
B. energy
C. magnetic field
D. magnetic force
B. energy
107
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
D. 1.6 x 10-19 Joules
108
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. Coulombs first law
B. Coulombs second law
C. Coulombs third law
D. Coulombs law or law of electrostatics
D. Coulombs law or law of electrostatics
109
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. Newtons first law
B. Newtons second law
C. Nortons law
D. Coulombs second law
D. Coulombs second law
110
Is usually used to detect the presence of electric charge.
A. experimental charge
B. unit charge
C. dipole
D. test charge
D. test charge
111
Test charge has a charge of
A. 0 Coulomb
B. +1 Coulomb
C. -1 Coulomb
D. Infinity
B. +1 Coulomb
112
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
D. +6 Coulomb
113
A combination of two charges, with equal charge magnitude but opposite signs.
A. magnetic dipole
B. static dipole
C. dynamic dipole
D. electric dipole
D. electric dipole
114
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
A. Electric field
115
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
D. Electromotive
116
The imaginary lines representing the electric field.
A. Electric field
B. Electric flux
C. Electric flux density
D. Electric lines of force
D. Electric lines of force
117
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.
D. All of the above.
118
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
B. Electric flux
119
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
C. Electric flux density
120
Electric lines of force leave and enter the charge surface at what angle?
A. 15°
B. 30°
C. 45°
D. 90°
D. 90°
121
Find the dielectric constant of air.
A. approximately 1
B. approximately 0
C. approximately 2
D. approximately 4
A. approximately 1
122
Electric field intensity is measured in terms of
A. Volts/meter
B. Newtons/meter
C. Watts/meter
D. Amperes/meter
A. Volts/meter
123
Electric field intensity is
A. a scalar quantity
B. a vector quantity
C. an absolute value
D. a relative value
B. a vector quantity
124
Electric flux is a/an ________ quantity.
A. scalar
B. vector
C. absolute
D. relative
A. scalar
125
Electric flux density is a/an ________ quantity.
A. scalar
B. vector
C. absolute
D. relative
B. vector
126
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
B. 6 Coulombs
127
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/m2
B. 2 C/m2
C. 4 C/m2
D. 6 C/m2
D. 6 C/m2
128
The measure of density of the electric charge
A. Electric gradient
B. Electric current
C. Electric charge
D. Electric potential
D. Electric potential
129
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
C. permittivity
130
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
A. 1/36π x 10-9 F/m
131
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
B. 1
132
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
B. 4.42 x 10-11 F/m
133
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
D. Joules
134
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.
B. It causes the field intensity to decrease.
135
Relative permittivity is also known as
A. dielectric constant
B. dielectric strength
C. isolation strength
D. permeability
A. dielectric constant
136
Most materials relative permittivity lies between
A. 0.01 1
B. 1 10
C. 10 50
D. 50 100
B. 1 10
137
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
B. electrostatics
138
The basic law for interaction of charged bodies at rest.
A. Charged law
B. Gauss law
C. Faradays law
D. Coulombs law
D. Coulombs law
139
The force between the two electrically charged body is called
A. electromotive force
B. electrostatic force
C. electromagnetic force
D. magnetic force
B. electrostatic force
140
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
A. directly proportional to the charge
141
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
D. Coulomb
142
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
B. 14.4 N
143
What will happen when two opposite charges get closer?
A. repels less
B. attracts less
C. repels more
D. attracts more
D. attracts more
144
The value of k in Coulombs electrostatic force equation ( F = kQ1Q2/r2 ) is oftentimes expressed as 1/4πεο. What is εο?
A. absolute permeability
B. absolute permittivity
C. relative permeability
D. relative permittivity
B. absolute permittivity
145
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
D. All of the above
146
Calculate the electric field intensity 10cm from a charge Q=5nC.
A. 450 N/C
B. 900 N/C
C. 4.5 x 103 N/C
D. 9.0 x 103 N/C
C. 4.5 x 103 N/C
147
Determine the magnitude of the electric field inside a sphere that encloses a net charge of 2μC.
A. 0 (zero)
B. 9 x 107 N/C
C. 1.8 x 108 N/C
D. infinite
A. 0 (zero)
148
Calculate the total electric field at the surface of a sphere of radius r=1cm, and enclosing a net charge of 2μC.
A. 0 (zero)
B. 9 x 107 N/C
C. 1.8 x 108 N/C
D. infinite
C. 1.8 x 108 N/C
149
A 2nC point charge will produce what potential at 2m away?
A. 4.0 Volts
B. 6.0 Volts
C. 7.5 Volts
D. 9.0 Volts
D. 9.0 Volts
150
A charged body in free space produces 10-V potential at a distance 25cn away. What will be the potential at 50cm away?
A. 5.0 Volts
B. 7.5 Volts
C. 10.0 Volts
D. 15.0 Volts
A. 5.0 Volts
151
What do you call the phenomenon whereby substance attracts pieces of iron?
A. Permeability
B. Magnetism
C. Naturalism
D. Electromagnetism
B. Magnetism
152
The condition in which a substance attracts pieces of iron is known as
A. Electromagnetism
B. Electrolysis
C. Magnetism
D. Magnetic Induction
C. Magnetism
153
A substance that attracts pieces iron is known as
A. magnet
B. conductor
C. ferrite
D. superconductor
A. magnet
154
A natural magnet
A. loadstone
B. carbon
C. lodestone
D. magnesium
C. lodestone
155
Group of magnetically aligned atoms.
A. Lattice
B. Crystal
C. Domain
D. Range
C. Domain
156
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
D. magnetic pole
157
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
C. Travels from north to south through the surrounding medium of a bar magnet
158
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
A. North Pole
159
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
B. Unit pole
160
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
D. magnetic axis
161
The phenomenon in which a substance becomes a magnet when placed near a magnet.
A. magnetic transfer
B. magnetic induction
C. electromagnetism
D. magnetism
B. magnetic induction
162
A force which causes a substance to become a magnet.
A. magnetizing force
B. magnetomotive
C. creative force
D. electromagnetic force
A. magnetizing force
163
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
D. Residual magnetism
164
Is the property of magnetic materials, which retain magnetism after the withdrawal of magnetizing force.
A. retentivity
B. permeability
C. reluctivity
D. susceptability
A. retentivity
165
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
C. a permanent magnet
166
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
A. soft magnetic materials
167
Materials that can be easily magnetized in both directions
A. soft magnetic materials
B. hard magnetic materials
C. diamagnetic
D. paramagnetic
A. soft magnetic materials
168
Ability of a material to conduct magnetic flux through it refers to
A. permittivity
B. permeability
C. reluctivity
D. conductivity
B. permeability
169
The ability to concentrate magnetic lines of force.
A. retentivity
B. permeability
C. susceptability
D. reluctivity
B. permeability
170
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
A. 4π x 10-7 H/m
171
The ratio of material permeability to the permeability of air or vacuum.
A. relative conductivity
B. relative permeability
C. inverse permeability
D. inverse permittivity
B. relative permeability
172
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
B. 1
173
Materials with permeability slightly less than that of free space.
A. diamagnetic
B. paramagnetic
C. ferromagnetic
D. antimagnetic
A. diamagnetic
174
Materials with permeability slightly greater than that of free space.
A. diamagnetic
B. paramagnetic
C. ferromagnetic
D. antimagnetic
B. paramagnetic
175
What do you call materials, which possess very high permeabilities?
A. diamagnetic
B. paramagnetic
C. ferromagnetic
D. antimagnetic
C. ferromagnetic
176
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
A. slightly greater than 1
177
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
D. The conductivity of the material for magnetic lines of force
178
Nonmetallic materials that has ferromagnetic properties.
A. termites
B. ferrites
C. ferrous
D. loadstone
B. ferrites
179
Cores of magnetic equipment use magnetic material which has
A. very low permeability
B. moderate permeability
C. low permeability
D. high permeability
D. high permeability
180
Hydrogen is an example of a _________ material.
A. diamagnetic
B. ferromagnetic
C. paramagnetic
D. magnetic
A. diamagnetic
181
Cobalt is an example of a _________ material.
A. diamagnetic
B. ferromagnetic
C. paramagnetic
D. magnetic
B. ferromagnetic
182
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
A. magnetic field
183
The imaginary lines representing the magnetic field.
A. magnetic field
B. magnetic flux
C. magnetic flux density
D. magnetic lines of force
D. magnetic lines of force
184
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
B. magnetic flux
185
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
C. magnetic flux density
186
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 magnets orientation with respect to the earths magnetic pole
C. either from north to south or south to north pole
187
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
C. magnetic flux
188
Magnetic lines of force are called
A. magnetic field
B. magnetic flux density
C. magnetic flux
D. electromagnetic field
C. magnetic flux
189
What is the unit of magnetic flux in SI system?
A. Weber
B. Maxwell
C. Tesla
D. Gauss
A. Weber
190
The unit of magnetic flux density in SI:
A. Gauss
B. Weber
C. Maxwell
D. Tesla
D. Tesla
191
A magnetic flux of 25,000 maxwell in an area of 5 sqcm. results in flux density of
A. 5,000 Gauss (G)
B. 125,000 G
C. 5,000 Tesla (T)
D. 125,000 T
A. 5,000 Gauss (G)
192
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
B. 2,000 G
193
What does a gaussmeter measure?
A. flux
B. magnetic field
C. magnetic flux density
D. mmf
C. magnetic flux density
194
The capacity of a substance to become magnetized. This is expressed as a ratio between the magnetization produced in a substance to the magnetizing force producing it.
A. magnetic conductivity
B. magnetic susceptibility
C. magnetic resistivity
D. magnetic reluctivity
B. magnetic susceptibility
195
The typical saturation flux density for most magnetic materials.
A. 0.1 Wb/m2
B. 2 Wb/m2
C. 10 Wb/m2
D. 20 Wb/m2
B. 2 Wb/m2
196
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
B. inversely proportional to the
197
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
D. increases four times
198
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
B. 2 N/Wb
199
Unit of permeability
A. Henry/meter (H/m)
B. Farad/meter (F/m)
C. Henry-meter (H-m)
D. Farad-meter (F-m)
A. Henry/meter (H/m)
200
The unit of permittivity
A. Henry/meter (H/m)
B. Farad/meter (F/m)
C. Henry-meter (H-m)
D. Farad-meter (F-m)
B. Farad/meter (F/m)
201
Magnetic intensity is
A. a vector quantity
B. a scalar quantity
C. an imaginary quantity
D. either a vector or scalar
A. a vector quantity
202
The Gauss is a unit of
A. permeability
B. electromagnetic force
C. magnetic force
D. magnetic flux density
D. magnetic flux density
203
What is the unit of flux in cgs?
A. Ampere-turn (At)
B. Coulomb/sec. (C/s)
C. Maxwell (Mx)
D. Gauss
C. Maxwell (Mx)
204
One Weber is equivalent to
A. 108 Maxwells
B. 106 Maxwells
C. 104 Maxwells
D. 102 Maxwells
A. 108 Maxwells
205
The equivalent of 1 x 109 Maxwells is
A. 1 Weber
B. 10 Weber
C. 100 Weber
D. 1,000 Weber
B. 10 Weber
206
A magnetic flux of 500,000,000 lines is equivalent to
A. 5 x 108 Maxwells
B. 5 Weber
C. 500 x 106 MAxwells
D. all of the above
D. all of the above
207
The unit of flux density in mks
A. Gauss
B. Weber/m2
C. Maxwell
D. Tesla
B. Weber/m2
208
What do you call the force that sets up or tends to set up magnetic flux in a magnetic circuit?
A. electromotive force
B. potential difference
C. magnetomotive force
D. dynamic force
C. magnetomotive force
209
Voltage in electrical circuits is analogous to _________ in magnetic circuits.
A. Ampere-turn
B. Magnetomotive force
C. Magnetizing force
D. Flux
B. Magnetomotive force
210
Electrical current is analogous to _________ in magnetic circuits.
A. Ampere-turn
B. Magnetomotive force
C. Magnetizing force
D. Flux
D. Flux
211
__________ capability is analogous to permeance.
A. Admittance
B. Conductance
C. Reluctance
D. Resistance
B. Conductance
212
Resistance in electrical circuits is analogous to _________ in magnetic circuits.
A. Conductance
B. Permeance
C. Elastance
D. reluctance
D. reluctance
213
The property of a material which opposes the creation of magnetic flux.
A. elastance
B. permeance
C. susceptance
D. reluctance
D. reluctance
214
The reciprocal of reluctance
A. conductance
B. permeance
C. elastance
D. capacitance
B. permeance
215
Permeance is analogous to
A. conductance
B. resistance
C. impedance
D. elastance
B. resistance
216
Is the reciprocal of reluctance and implies the readiness of a material to develop magnetic flux.
A. elastance
B. permeance
C. susceptance
D. conductance
B. permeance
217
Magnetic circuit property that permits flux.
A. elastance
B. permeance
C. susceptance
D. conductance
B. permeance
218
It is easier to establish flux line in soft iron than it is to establish them in air, this is because iron has a lower
A. Permeance
B. Inductance
C. elastance
D. reluctance
D. reluctance
219
The Oersted (Oe) is the same as
A. 1 Gb/cm
B. 1 Gb/m
C. 10 Gb/cm
D. 10 Gb/cm
A. 1 Gb/cm
220
The unit of reluctance
A. Gilbert
B. Tesla
C. At/Wb
D. Gauss
C. At/Wb
221
It is the specific reluctance of a material.
A. resistivity
B. retentivity
C. reluctivity
D. permeability
C. reluctivity
222
At/m is a unit of
A. magnetic field
B. reluctance
C. magnetizing force
D. magnetic power
C. magnetizing force
223
Magnetomotive force has a unit of
A. Volt (V)
B. Watt (W)
C. Joule (J)
D. Ampere-turn (At)
D. Ampere-turn (At)
224
The cgs unit of magnetomotive force
A. Volt
B. Weber
C. Gilbert
D. Ampere-turn
C. Gilbert
225
One Gilbert is equal to
A. 0.0796 At
B. 0.796 At
C. 7.96 At
D. 79.6 At
B. 0.796 At
226
One Ampere-turn (At) is equivalent to
A. 0.126 Gilbert
B.1.260 Gilberts
C. 12.60 Gilberts
D 126 Gilberts
B.1.260 Gilberts
227
The current needed for a coil of 200 turns to provide a 400 ampere turn magnetizing force is
A. 2 A
B. 4 A
C. 6 A
D. 8 A
A. 2 A
228
Determine the ampere-turns when a 10 V battery is connected across a solenoid having 100 turns and a resistance of 5 Ω.
A. 50 At
B. 200 At
C. 100 At
D. 1,000 At
B. 200 At
229
What is residual magnetism?
A. The external magnetic field when the current is flowing through the exciting coil.
B. The flux density, which exist in the iron core when the magnetic field intensity is reduced to zero.
C. The flux density, which exist in the iron core when the magnetic field intensity is at its maximum value.
D. The flux density when the magnetic core is saturated.
B. The flux density, which exist in the iron core when the magnetic field intensity is reduced to zero.
230
When you demagnetize property by applying an AC field and then gradually reduced it to zero, it is called
A. damping
B. decaying
C. degaussing
D. gaussing
C. degaussing
231
In a magnetic circuit, a flux that drifts away from its intended path is called
A. lost flux
B. linked flux
C. drift flux
D. leakage flux
D. leakage flux
232
Is the quantity of magnetizing force needed to counter balance the residual magnetism of a magnetic material.
A. hysteresis
B. degaussing
C. retentivity
D. coercivity
D. coercivity
233
What do you call the loss of electrical energy in counter balancing the residual magnetism in each cycle?
A. hysteresis
B. magnetomotive
C. leakage
D. coercivity
D. coercivity
234
The amount of magnetic field needed to remove residual magnetism from a transformer core during each half cycle is called the
A. coercive force
B. residual field
C. hysteresis field
D. demagnetizing force
A. coercive force
235
If a wire coil has 100 turns and carries 1.3 A of current, calculate the magnetomotive force in Gilbert.
A. 163.3
B. 16.33
C. 1.633
D. 0.1633
A. 163.3
236
An advantage of an electromagnet over a permanent magnet
A. An electromagnet can be demagnetized
B. An electromagnet is simpler
C. An electromagnet is cheaper
D. An electromagnet can be switched ON and OFF
D. An electromagnet can be switched ON and OFF
237
Electromagnet whose core is in the form of a close magnetic ring
A. solenoid
B. relay
C. toroid
D. circular
C. toroid
238
Magnetic flux can always be attributed to
A. static charged particles
B. motion of charge particles
C. static electric field
D. every applied potential
B. motion of charge particles
239
What is a magnetic field?
A. A force set up when current flows through a conductor.
B. A force set up when a charged body is at static.
C. The space between two electrically charged particles.
D. The space around a conductor.
A. A force set up when current flows through a conductor.
240
Which of the following determines the strength of a magnetic field around a conductor?
A. amount of current
B. diameter of the conductor
C. length of the conductor
D. amount of voltage
A. amount of current
241
The magnetic flux around a straight, current carrying wire, is stronger
A. near the edge
B. near the wire
C. at the center
D. at both edge
B. near the wire
242
In what direction is the magnetic field about a conductor when current is flowing?
A. In a direction determined by the left-hand rule.
B. Always in a clock wise direction.
C. Always in a counter clockwise direction.
D. In a direction determined by the right-hand screw rule.
A. In a direction determined by the left-hand rule.
243
If the electrical current carried by each of the two long parallel wire is doubled, and their separation is also doubled, the force between them
A. also doubles
B. increases by a factor of four
C. decreases by a factor of four
D. decreases by a factor of two
A. also doubles
244
Reversing the flow of current in a circuit
A. reverses the magnetic polarity
B. increase the magnetic field intensity
C.decreases the magnetic intensity
D. enhances hysteresis
A. reverses the magnetic polarity
245
Is used to maintain strength of magnetic field.
A. storer
B. energizer
C. gausser
D. keeper
D. keeper
246
What law that describes the force of attraction or repulsion between two magnetic poles is directly proportional to their strengths?
A. Coulombs first law
B. Coulombs second law
C. Amperes law
D. Gauss law
A. Coulombs first law
247
What is the law whereby the force of attraction or repulsion between poles is inversely proportional to the square of the distance between them?
A. Coulombs first law
B. Coulombs second law
C. Coulombs third law
D. Coulombs law
B. Coulombs second law
248
The physical motion resulting from the forces of magnetic fields.
A. motor action
B. linear motion
C. rectilinear motion
D. generator action
A. motor action
249
What law in electronics where an induced current will be in such a direction that its own magnetic field will oppose the magnetic field that produces the same?
A. Electromagnetic law
B. Nortons law
C. Lenz law
D. Maxwell law
C. Lenz law
250
A changing magnetic field
A. produces an electric field
B. induces potential
C. produces a fluctuating electric field
D. produces a steady electric field
B. induces potential
251
The emf induced in a coil due to the change of its flux linked with it is called
A. mutual emf
B. crossfire induced emf
C. self induced emf
D. virtually induced emf
C. self induced emf
252
If two coils are close enough together for their magnetic fields to interact, a change in current in one will induce a corresponding voltage in the other, This condition is known as
A. self-inductance
B. mutual inductance
C. crossfire inductance
D. linked inductance
B. mutual inductance
253
If the magnetic flux through a coil changes, the induced EMF acts in such a direction as to
A. oppose that change
B. magnify that change
C. augment that change
D. amplify that change
A. oppose that change
254
When a conductor is moved through a magnetic field a voltage is always induced. The amount of voltage is always proportional to
A. the diameter of the conductor used
B. the length of the conductor
C. the distance of the conductor from the field
D. the rate at which the conductor is moved
D. the rate at which the conductor is moved
255
The term of energy that is stored in an electromagnetic or electrostatic field
A. kinetic energy
B. static energy
C. dynamic energy
D. potential energy
D. potential energy
256
What is meant by back EMF?
A. A voltage that is applied in the reverse direction.
B. An EMF that is dude to the fly wheel effect.
C. An EMF that is generated from the back of an electromagnet.
D. A voltage that opposes the applied EMF.
D. A voltage that opposes the applied EMF.
257
When current in a conductor increases, Lenz law states that the self-induced potential will
A. produce current opposite to the increasing current
B. tend to produce more magnetic field
C. tend to augment the increase in current
D. produce current with the same direction to the increasing current
A. produce current opposite to the increasing current
258
If a magnetic flux occurs across 100 turns at a rate of 2 Wb/sec. What is the induced voltage as per Faradays law?
A. 100 V
B. 400 V
C. 200 V
D. 800 V
C. 200 V
259
The circuit element that is used represent the energy stored in a magnetic field.
A. resistance
B. capacitance
C. inductance
D. elastance
C. inductance
260
Which of the given below can produce the most induced voltage?
A. 1 A dc
B. 1 A, 60 Hz
C. 50 A dc
D. 1 A, 400 Hz
D. 1 A, 400 Hz
261
In all cases of electromagnetic induction, the current set-up by an induced voltage tends to create flux whose direction opposes any change in the existing flux. This law is called
A. Amperes law
B. Lenz law
C. Coulombs law
D. Faradays law
B. Lenz law
262
In electromagnetism, what law that determines the polarity of an induced voltage?
A. Amperes law
B. Lenz law
C. Coulombs law
D. Faradays law
B. Lenz law
263
In electromagnetism, what law that determines the amount of induced voltage?
A. Amperes law
B. Lenz law
C. Coulombs law
D. Faraday’s law
D. Faraday’s law
264
Electromotive force (emf) is induced whenever a conductor cuts magnetic flux
A. Faradays first law
B. Faradays second law
C. Coulombs first law
D. Coulombs second law
A. Faradays first law
265
The magnitude of electromotive force (emf) that is induced when a conductor cuts magnetic flux is directly proportional to its rate.
A. Faradays first law
B. Faradays second law
C. Coulombs first law
D. Coulombs second law
B. Faradays second law
266
The effect that describes the ability of a mechanically stressed ferromagnetic wire to recognize rapid switching of magnetization when subjected to a DC magnetic field.
A. Wiegand effect
B. Wertheim effect
C. Wiedemann effect
D. Wall effect
A. Wiegand effect
267
The concept whereby a small voltage is generated by a conductor with current in an external magnetic field is known as
A. Wiegand effect
B. Hall effect
C. Wiedemann effect
D. Wall effect
B. Hall effect
268
_________ is called the magnetic field.
A. The force that drives current through a resistor
B. Current flow through space around a permanent magnet
C. The force between the plates of charged capacitor
D. A force set up when current flow through a conductor
D. A force set up when current flow through a conductor
269
The natural magnet refers to
A. steel
B. soft iron
C. magnesia
D. loadstone (lodestone)
D. loadstone (lodestone)
270
The force between two magnetic poles in relation to their pole strength is ________.
A. not related
B. inversely proportional
C. directly proportional
D. Butindependent
C. directly proportional
