Test 1 Flashcards
What composes all matter whether a liquid, solid, or gas?
A. Atoms
B. Electrons
C. Protons
D. Neutrons
A. Atoms
Which of the following is not a basic part of an atom?
A. Electron
B. Proton
C. Neutron
D. Coulomb
D. Coulomb
What is the smallest element of a matter?
A. atom
B. molecule
C. crystal
D. wafer
A. atom
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. atomic structure
Approximate diameter of an atom
A. 10-10 µµm
B. 10-10 µm
C. 10-10 mm
D. 10-10 m
D. 10-10 m
The lightest kind of atom or element
A. Helium
B. Oxygen
C. Hydrogen
D. Titanium
C. Hydrogen
Known as the simplest type of atom.
A. Hydrogen
B. Oxygen
C. Helium
D. Nitrogen
A. Hydrogen
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
B. 1.1 x 10-10 µm
A commonly used model in predicting the atomic structure of a material.
A. String model
B. Wave model
C. Particle model
D. Bohr model
D. Bohr model
Is at the center of an atomic structure in a Bohr model.
A. electrons
B. protons
C. neutrons
D. nucleus
D. nucleus
The nucleus of an atom is normally
A. neutral
B. positively charged
C. negatively charged
D. either positively or negatively charged
A. neutral
What particles that revolve around the positive nucleus?
A. electrons
B. protons
C. neutrons
D. electrons & protons
A. electrons
In electricity, positive electric charge refers to ____________.
A. protons
B. neutrons
C. electrons
D. atoms
A. protons
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. 1.6022 x 10-19 C
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
B. 1.6726 x 10-27 Kg
Protons are about _________ heavier than electrons.
A. 1,800 times
B. less than thrice
C. less
D. twice
A. 1,800 times
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
D. 1,836 electrons
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. Ne = 2n2
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
C. quantum
Maximum number of orbiting electrons at the first or K shell
A. 2
B. 4
C. 6
D. 8
A. 2
Electron is derived from the Greek name elektron which means
A. huge
B. tiny
C. particle
D. amber
D. amber
Electric charge of neutron is the same as
A. proton
B. electron
C. current
D. atom
D. atom
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
C. neutrons
The atomic number of an element is determined by the number of
A. electrons
B. valence electrons
C. protons
D. protons or neutrons
C. protons
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
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
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
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
Electrons at the conduction band are called
A. free electrons
B. valence electrons
C. deep state electrons
D. shallow state electrons
A. free electrons
_____________ are electrons at the outer shell
A. Inside shell electrons
B. Conductor electrons
C. Outside shell electrons
D. Valence electrons
D. Valence electrons
Electrons at the outermost shell are called
A. free electrons
B. valence electrons
C. deep state electrons
D. shallow state electrons
B. valence electrons
Which material has more free electrons?
A. Conductor
B. insulators
C. mica
D. dielectric
A. Conductor
Which material has the least number of valence electrons?
A. conductor
B. semiconductor
C. insulator
D. semi-insulator
A. conductor
What elements possess four valence electrons?
A. Insulators
B. Semi-insulators
C. Semiconductors
D. Conductors
C. Semiconductors
A good conductor has how many valence electrons?
A.1
B. 2
C. 4
D. 8
A.1
Materials that might have eight valence electrons
A. conductor
B. insulator
C. semiconductor
D. semi-insulator
B. insulator
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
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
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.
A material that contains an abundance of free carrier is called
A. insulator
B. semi-insulator
C. conductor
D. semiconductor
C. conductor
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
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
__________ has a unit of electronvolt(eV).
A. Charge
B. Potential difference
C. Energy
D. Current
C. Energy
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
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)
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)
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
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
A factor that does not affect the resistance of the material.
A. atomic structure
B. mass
C. length
D. cross-sectional area
B. mass
Copper atom has how many protons?
A. 1
B. 4
C. 8
D. 29
D. 29
Ion is __________.
A. an atom with unbalanced charges
B. free electron
C. proton
D. nucleus without protons
A. an atom with unbalanced charges
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
When an atom gains an additional _________, it results to a negative ion.
A. neutron
B. proton
C. electron
D. atom
C. electron
An electrical insulator can be made a conductor by
A. ionizing
B. electroplating
C. oxidizing
D. metalization
A. ionizing
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
Dielectric is another name for
A. conductor
B. semiconductor
C. insulator
D. semi-insulator
C. insulator
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
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
Isotope means, the same element but with different number of
A. electrons
B. neutrons
C. protons
D. atoms
B. neutrons
The particles that make up the lattice in ionic crystal
A. molecules
B. ions
C. electrons
D. neutrons
C. electrons
A structure for solids in which the position of atoms are predetermined
A. Crystalline
B. Polycrystalline
C. Lattice
D. Non-Crystalline
A. Crystalline
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
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
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
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
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
A charged atom is also known as
A. ion
B. anion
C. cation
D. domain
A. ion
An atom or group of atoms that carries a net electric charge is called
A. ion
B. anion
C. cation
D. domain
A. ion
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
A positive ion has
A. excess of electrons
B. excess of neutrons
C. lack of electrons
D. lack of protons
C. lack of electrons
What do you call a positively charged ion?
A. cathode
B. anion
C. cation
D. domain
C. cation
What do you call a negatively charged ion?
A. electron
B. anion
C. cation
D. domain
B. anion
__________ 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
Is a process by which an atom is constantly losing and then regaining electrons?
A. oxidation
B. passivation
C. metallization
D. ionization
D. ionization
The process in which atoms are changed into ions.
A. oxidation
B. passivation
C. metallization
D. ionization
D. ionization
Gases with charged particles.
A. inert
B. plasma
C. conductive
D. reactive
B. plasma
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
Coulomb is the SI unit of charge, how about in cgs?
A. Statcoulomb
B. electron volt
C. electron unit
D. static unit
A. Statcoulomb
Statcoulomb is also known as
A. electrostatic unit (esu)
B. electron volt
C. electron unit
D. static unit
A. electrostatic unit (esu)
An isolated body under normal condition is always
A. neutral
B. positively charged
C. negatively charged
D. ionized
A. neutral
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
The net movement of charged particles in one direction or another.
A. flow
B. current
C. drift current
D. diffusion current
B. current
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
The unit of current.
A. Ampere
B. Ampere/sec.
C. Ampere-sec.
D. Ampere-hr.
A. Ampere
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
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
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.
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
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
The greater the diameter of a wire, the _______ is the resistance.
A. greater
B. lesser
C. harder
D. bigger
B. lesser
The longer the wire the ________ is the resistance
A. higher
B. lesser
C. harder
D. smaller
A. higher
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
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
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
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
the reciprocal of resistance
A. permeance
B. elastance
C. inductance
D. conductance
D. conductance
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
What happens in the resistance of copper wire when its temperature is raised?
A. decreased
B. steady
C. increased
D. zero
C. increased
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
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
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
________ is one factor that does not affect resistance.
A. Cross sectional area
B. Resistivity
C. Mass
D. Length
C. Mass
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
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
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
Electron volt (eV) is a unit of
A. power
B. energy
C. magnetic field
D. magnetic force
B. energy
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
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
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
Is usually used to detect the presence of electric charge.
A. experimental charge
B. unit charge
C. dipole
D. test charge
D. test charge
Test charge has a charge of
A. 0 Coulomb
B. +1 Coulomb
C. -1 Coulomb
D. Infinity
B. +1 Coulomb
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
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
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
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
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
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.
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
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
Electric lines of force leave and enter the charge surface at what angle?
A. 15°
B. 30°
C. 45°
D. 90°
D. 90°
Find the dielectric constant of air.
A. approximately 1
B. approximately 0
C. approximately 2
D. approximately 4
A. approximately 1
Electric field intensity is measured in terms of
A. Volts/meter
B. Newtons/meter
C. Watts/meter
D. Amperes/meter
A. Volts/meter
Electric field intensity is
A. a scalar quantity
B. a vector quantity
C. an absolute value
D. a relative value
B. a vector quantity
Electric flux is a/an ________ quantity.
A. scalar
B. vector
C. absolute
D. relative
A. scalar
Electric flux density is a/an ________ quantity.
A. scalar
B. vector
C. absolute
D. relative
B. vector
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
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
The measure of density of the electric charge
A. Electric gradient
B. Electric current
C. Electric charge
D. Electric potential
D. Electric potential
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
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
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
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
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
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.
Relative permittivity is also known as
A. dielectric constant
B. dielectric strength
C. isolation strength
D. permeability
A. dielectric constant
Most materials relative permittivity lies between
A. 0.01 1
B. 1 10
C. 10 50
D. 50 100
B. 1 10
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
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
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
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
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
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
What will happen when two opposite charges get closer?
A. repels less
B. attracts less
C. repels more
D. attracts more
D. attracts more
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
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
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
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)
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
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
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
What do you call the phenomenon whereby substance attracts pieces of iron?
A. Permeability
B. Magnetism
C. Naturalism
D. Electromagnetism
B. Magnetism
The condition in which a substance attracts pieces of iron is known as
A. Electromagnetism
B. Electrolysis
C. Magnetism
D. Magnetic Induction
C. Magnetism
A substance that attracts pieces iron is known as
A. magnet
B. conductor
C. ferrite
D. superconductor
A. magnet
A natural magnet
A. loadstone
B. carbon
C. lodestone
D. magnesium
C. lodestone
Group of magnetically aligned atoms.
A. Lattice
B. Crystal
C. Domain
D. Range
C. Domain
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
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
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
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
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
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
A force which causes a substance to become a magnet.
A. magnetizing force
B. magnetomotive
C. creative force
D. electromagnetic force
A. magnetizing force
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
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
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
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
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
Ability of a material to conduct magnetic flux through it refers to
A. permittivity
B. permeability
C. reluctivity
D. conductivity
B. permeability
The ability to concentrate magnetic lines of force.
A. retentivity
B. permeability
C. susceptability
D. reluctivity
B. permeability
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
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
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
Materials with permeability slightly less than that of free space.
A. diamagnetic
B. paramagnetic
C. ferromagnetic
D. antimagnetic
A. diamagnetic
Materials with permeability slightly greater than that of free space.
A. diamagnetic
B. paramagnetic
C. ferromagnetic
D. antimagnetic
B. paramagnetic
What do you call materials, which possess very high permeabilities?
A. diamagnetic
B. paramagnetic
C. ferromagnetic
D. antimagnetic
C. ferromagnetic
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
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
Nonmetallic materials that has ferromagnetic properties.
A. termites
B. ferrites
C. ferrous
D. loadstone
B. ferrites
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
Hydrogen is an example of a _________ material.
A. diamagnetic
B. ferromagnetic
C. paramagnetic
D. magnetic
A. diamagnetic
Cobalt is an example of a _________ material.
A. diamagnetic
B. ferromagnetic
C. paramagnetic
D. magnetic
B. ferromagnetic
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
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
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
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
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
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
Magnetic lines of force are called
A. magnetic field
B. magnetic flux density
C. magnetic flux
D. electromagnetic field
C. magnetic flux
What is the unit of magnetic flux in SI system?
A. Weber
B. Maxwell
C. Tesla
D. Gauss
A. Weber
The unit of magnetic flux density in SI:
A. Gauss
B. Weber
C. Maxwell
D. Tesla
D. Tesla
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)
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
What does a gaussmeter measure?
A. flux
B. magnetic field
C. magnetic flux density
D. mmf
C. magnetic flux density
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
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
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
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
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
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)
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)
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
The Gauss is a unit of
A. permeability
B. electromagnetic force
C. magnetic force
D. magnetic flux density
D. magnetic flux density
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)
One Weber is equivalent to
A. 108 Maxwells
B. 106 Maxwells
C. 104 Maxwells
D. 102 Maxwells
A. 108 Maxwells
The equivalent of 1 x 109 Maxwells is
A. 1 Weber
B. 10 Weber
C. 100 Weber
D. 1,000 Weber
B. 10 Weber
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
The unit of flux density in mks
A. Gauss
B. Weber/m2
C. Maxwell
D. Tesla
B. Weber/m2
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
Voltage in electrical circuits is analogous to _________ in magnetic circuits.
A. Ampere-turn
B. Magnetomotive force
C. Magnetizing force
D. Flux
B. Magnetomotive force
Electrical current is analogous to _________ in magnetic circuits.
A. Ampere-turn
B. Magnetomotive force
C. Magnetizing force
D. Flux
D. Flux
__________ capability is analogous to permeance.
A. Admittance
B. Conductance
C. Reluctance
D. Resistance
B. Conductance
Resistance in electrical circuits is analogous to _________ in magnetic circuits.
A. Conductance
B. Permeance
C. Elastance
D. reluctance
D. reluctance
The property of a material which opposes the creation of magnetic flux.
A. elastance
B. permeance
C. susceptance
D. reluctance
D. reluctance
The reciprocal of reluctance
A. conductance
B. permeance
C. elastance
D. capacitance
B. permeance
Permeance is analogous to
A. conductance
B. resistance
C. impedance
D. elastance
B. resistance
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
Magnetic circuit property that permits flux.
A. elastance
B. permeance
C. susceptance
D. conductance
B. permeance
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
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
The unit of reluctance
A. Gilbert
B. Tesla
C. At/Wb
D. Gauss
C. At/Wb
It is the specific reluctance of a material.
A. resistivity
B. retentivity
C. reluctivity
D. permeability
C. reluctivity
At/m is a unit of
A. magnetic field
B. reluctance
C. magnetizing force
D. magnetic power
C. magnetizing force
Magnetomotive force has a unit of
A. Volt (V)
B. Watt (W)
C. Joule (J)
D. Ampere-turn (At)
D. Ampere-turn (At)
The cgs unit of magnetomotive force
A. Volt
B. Weber
C. Gilbert
D. Ampere-turn
C. Gilbert
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
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
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
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
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.
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
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
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
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
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
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
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
Electromagnet whose core is in the form of a close magnetic ring
A. solenoid
B. relay
C. toroid
D. circular
C. toroid
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
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.
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
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
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.
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
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
Is used to maintain strength of magnetic field.
A. storer
B. energizer
C. gausser
D. keeper
D. keeper
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
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
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
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
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
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
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
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
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
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
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.
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
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
The circuit element that is used represent the energy stored in a magnetic field.
A. resistance
B. capacitance
C. inductance
D. elastance
C. inductance
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
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
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
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
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
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
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
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
_________ 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
The natural magnet refers to
A. steel
B. soft iron
C. magnesia
D. loadstone (lodestone)
D. loadstone (lodestone)
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
