3001(elecs)
. Calculate the permeability (in T/A. 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
A
. Materials whose permeabilities are slightly greater than that of free space A. Paramagnetic B. Non- magnetic C. Ferromagnetic D. Diamagnetic
A
. Refers to the magnetic lines A. Flux B. Hysteresis C. Current D. Magnetomotive force
A
.One of the common application of an air- cored choke. A. Radio frequency B. Audio frequency C. Power supply D. Power transformer
A
.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
A
.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
A
5.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
A
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
A
A good conductor has how many valence electrons? A. 1 B. 4 C. 2 D. 8
A
A negative ion results when an atom gains an additional A. Electron B. Proton C. Neutron D. Atom
A
All magnetic field originates from A. moving electric charge B. Iron atoms C. Magnetic domain D. Permanent magnets
A
An alloy of 22 percent iron and 78 per cent nickel. A. Permalloy B. Alnico C. Constantan D. Manganin
A
An electron- volt (eV) is a unit of A. Energy B. Potential difference C. Charge D. Momentum
A
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)
A
Electron is a Greek word for A. amber B. Fire C. Stone D. Heat
A
Flux density is measured in A. Tesia B. Weber C. Ampere- turn D. Maxwell
A
Germanium atom has protons and electrons. A. 32, 32 B. 32, 42 C. 42, 32 D. 34, 34
A
How many electrons are needed in the valence orbit to give a material's stability? A. 8 B. 4 C. 6 D. 5
A
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' D. 2 x 10'3
A
In electro-mechanical conversion devices like generators and motors the reason whya 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
A
Lenz's law is the consequence of the law of conservation of A. Energy B. Charge C. Field lines D. Momentum
A
Mmf in a magnetic circuit corresponds to in an electric circuit A. Emf B. Voltage drop C. Electric Field Intensity D. Potential gradient
A
One oersted (Oe) is equivalent to Gb/cm. A. B. 10 C. 100 D. 1000
A
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
A
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
A
Permeance is analogous to A. Conductance B. Reluctance C. Admittance D. Resistance
A
Refers to the non- metallic materials that have the ferromagnetic properties of iron. A. Ferrites B. Ferromagnetic C. Diamagnetic D. Paramagnetic
A
Steel is hard to magnetize because of its A. Low permeability B. High permeability C. High density D. High retentivity
A
The air space between poles of magnets A. Air gap B. Free space C. Vacuum D. Atmosphere
A
The conduction of electricity across the surface of a dielectric is called A. creepage B. skin effect C. surface effect D. crosstalk
A
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
A
.Cobalt is an example of a material. A. Paramagnetic B. Diamagnetic C. Ferromagnetic D. Non- magnetic
C
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
A
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
A
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
A
The magnetic field of a magnetized iron bar when strongly heated A. Becomes weaker B. Becomes stronger C. Reverses in direction D. is unchanged
A
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
A
The magnetic potential in a magnetic circuit can be measured in terms of A. Mmf B. Emf C. Farad D. Coulomb
A
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
A
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
A
The phenomenon by which a subtracts pieces of iron A. Magnetism B. Electromagnetism C. Naturalism D. Materialism
A
The physical motion resulting from the forces of magnetic fields is called A. Motor action B. Rotation C. Repulsion D. Torque action
A
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
A
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
A
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
A
The quantity 10'6 maxwells is equivalent to one A. Weber B. Gauss C. Gilbert D. Tesla
A
The ratio of the permeability of material to the permiabiity of air or vacuum. A. Relative permeability B. Relative permittivity C. Relative conductivity D. Relative reluctivity
A
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
A
The tiniest element of matter A. Atom B. Proton C. Electron D. Neutron
A
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
A
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
A
What is the cgs unit of magnetomotive force? A. Gilbert B. Ampere- turn C. Maxwell D. Weber
A
What is the diameter of an atom? A. About tOA-tO m B. About 10"-10 cm C. About 10"-10 mm D. About 10"-10 µm
A
What is the reluctance of a magnetic path having a length of 2x 10'-3m and crosssectional area of 2.5 x 10'-3 m'2? A. 6366 A.t/Wb B. 6000 A.t/Wb C. 8x10'-3 A.t/Wb D. 0.8 A.t/Wb
A
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
A
Which of the following electric quantities is vector in character? A. Field B. Charge C. Energy D. Potential Difference
A
Which of the following has the least number of valence electrons? A. Conductor B. Semiconductor C. Insulator D. Semi- insulator
A
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
A
Who demonstrated the theory of electromagnetic induction in 1831? A. Michael Faraday B. Andre Ampere C. James Clerk Maxwell D. Charles Coulomb
A
Who discovered superconductivity in 1911? A. Kamerlingh Onnes B. Alex Muller C. Geory Bednorz D. Charles Coulomb
A
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
A
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
A
.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
B
9.One ampere- turn is equivalent to gilberts A. 1.16 B. 1.26 C. 1.36 D. 1.46
B
A germanium atom has an atomic weight of 72. How many neutrons are there? A. 32 B. 40 C. 34 D. 36
B
A magnetic flux of 2.5 x10'4 Wb through an area of 5 x10'4 square meters results in A. 5 Wb B. 0.5 Tesia of flux density C. 5x 10'-5 Wb of flux D. 5000 Tesia of flux density
B
Amorphous solid is also called A. Crystalline B. Non- crystalline C. Polycrystalline D. Homogenous
B
Defined as a closed path in which magnetic induction or flux flows A. Electric circuit B. Magnetic circuit C. Electronic circuit D. Electromagnetic circuit
B
Hydrogen is an example of a material. A. Paramagneti c B. Diamagnetic C. Ferromagnetic D. Non- magnetic
B
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
B
One that has magnetic poles produced by internal atomic structure with no external current necessary A. Diamagnetic B. Permanent magnets C. Paramagnetic D. Electromagnetic
B
Referred to as the specific reluctance of a material A. Resistivity B. Reluctivity C. Conductivity D. Permeability
B
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
B
The K shell or the first shell has how many permissible number of orbiting electrons? A. I B. 2 C. 3 D. 4
B
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
B
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
B
The current of electric circuit is analogous to which quantity of a magnetic circuit A. Mmf B. Flux C. Flux density D. Reluctivity
B
The emission of electrons from hot bodies is called A. Radiation effect B. Edison effect C. Skin effect D. Half effect
B
The force between two magnetic poles is their polesstrength. A. equal to B. directly proportionalto C. inversely proportional to D. directly proportional to the square root of
B
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
B
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
B
The magnetic flux of 2000 lines is how many Maxwells? A. 1000 B. 2000 C. 4000 D. 8000
B
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
B
The property of a material which opposes the creation of magnetic flux in it A. Resistance B. Reluctance C. Permeance D. Conductance
B
The simplest type of atom to exist is the atom. A. Helium B. Hydrogen C. Boron D. Oxygen
B
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
B
What is the SI unit of magnetic flux? A. Tesla B. Weber C. Maxwell D. Gauss
B
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
B
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
B
When a wire loop is rotated in a magnetic field the direction of the induced emf changes one in every revolution A. 1/3 B. 1/2 C. 1/4 D. 2/3
B
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
B
Which of the following is a vector quantity? A. Magnetic potential B. Magnetic field intensity C. Magnetic permeability D. Flux density
B
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
B
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
B
. A substance that attracts pieces iron A. Conductor B. Semiconductor C. Magnet D. All of the above
C
. 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
C
.An alloy of 40 percent iron and 60 percent nickel. A. Alnico B. Permallo y C. Hipernik D. Manganin
C
.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
C
7. Used to maintain strength of magnetic field A. Container B. Air gap C. Keeper D. Source
C
A 6- V battery is connected across a solenoid of 100 turns having a resistance of 2 n, Calculate the number of ampere turns? A. 100 B. 50 C. 300 D. 600
C
A group of magnetically aligned atoms is called A. Range B. Lattice C. Domain D. Crystal
C
A law establishing the fact that the algebraic su 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
C
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
C
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
C
A magnetic material losses its ferromagnetic properties at a point called A. Curie temperature B. Inferred absolute temperature C. Room temperature D. Absolute temperature
C
An atom or a group of atoms that carries a net electric charge. A. Positive ion B. Negative ion C. Ion D. Electron
C
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
C
Calculate the flux density that will be produced by the field intensity of 2000 a. 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
C
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
C
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
C
How many neutrons does a copper atom have? A. 32 B. 33 C. 34 D. 29
C
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
C
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
C
It is the reciprocal of reluctance and implies the case of readiness with which magnetic flux is developed. A. Resistance B. Conductanc e C. Permeance D. Inductance
C
Magnetic effects of the earth as a huge magnet with north and south poles. A. Diamagnetic B. Ferromagnetic C. Terrestrial magnetism D. Terrestrial ferromagnetism
C
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
C
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
C
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
C
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
C
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
C
The customary energy unit in atomic and nuclear physics is A. Joule B. Voltcoulomb C. electron-volt D. Walt- second
C
The diameter of a hydrogen atom is approximately cm. A. 1.1 x 1Q'-6 B. 1.1 x 1Q'-7 C. 1.1 x 10"-8 D. 1.1 x 1Q'-9
C
The energy stored in an electrostatic field or electromagnetic field is called A. Electromagnetic energy B. Kinetic energy C. Potential energy D. Rest energy
C
The evaporation of electrons from a heated surface is called A. Radiation B. Convection C. Thermionic emission D. Conduction
C
The force of attraction or repulsion between two magnetic poles is directly proportional to their strengths. A. Newton's first law B. Faraday's first law of electromagnetic induction C. Coulomb's first law D. Coulomb's second law
C
The idea of preventing one component from affecting another through their common electric and magnetic field is referred to as A. Hall effect B. Groundin g C. Shielding D. Limiting
C
The lagging effect between flux density of the material and the magnetizing force applied A. Permeance B. Eddy current C. Hysteresis D. Reluctance
C
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
C
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
C
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
C
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
C
The straight line passing through the two poles of magnet is called A. Real axis B. Cartesian axis C. Magnetic axis D. Imaginary axis
C
The unit of flux is in cgssystem. A. Tesia B. Gilbert C. Maxwell D. Oersted
C
What is the unit of magnetomotive force? A. Volt B. Tesla C. Ampere- turn D. Weber
C
What is the unit of reluctance? A. Maxwell B. Gauss C. At/Wb D. Weber
C
What revolves about the positive nucleus in a definite orbit? A. Atom B. Proton C. Electron D. Neutron
C
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. Covalen t C. Metallic D. Van der Waals
C
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
C
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
C
Which element has four valence electrons? A. Conductor B. Insulator C. Semiconductor D. Semi- insulator
C
Which of the following is a natural magnet? A. Steel B. Magnesia C. Lodestone D. Soft iron
C
Who developed the electromagnetic theory of light in 1862? A. Heinrich Rudolf Hertz B. Wilhelm Rontgen C. James Clerk Maxwell D. Andre Ampere
C
is an electromagnet with its core in the form of a close magnetic ring. A. Solenoid B. Paraboloid C. Toroid D. Cycloid
C
. 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
D
. Gases whose particles are charged are known as A. Conductors B. Insulators C. Gaseous Conductors D. Plasma
D
. 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
D
. 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
D
.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
D
.Electrons at the outer shell are called A. Outer shell electrons B. Inner shell electrons C. Semiconductor electrons D. Valence electrons
D
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
D
A t/m is a unit of A. Mmf B. Emf C. Reluctance D. Magnetizing force
D
All matters (gas, liquid and solid) are composed of A. Neutrons B. Particles C. Electron s D. Atoms
D
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
D
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
D
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
D
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
D
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
D
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
D
If a 20 V potential is applied across a relay coil with 50 turns having 1 Q 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
D
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
D
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
D
Magnetic fields do not interact with A. Moving permanent magnets B. Stationary permanent magnets C. Moving electric charges D. Stationary electric charges
D
Magnetic intensity is a A. Phasor quantity B. Physical quantity C. Scalar quantity D. Vector quantity
D
Ohm's law can be used only to a circuit or component. A. Unilateral B. Exponential C. Trivalen t D. Linear
D
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.
D
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
D
The ability of a material to conduct magnetic flux through it. A. Permittivity B. Reluctivity C. Conductivity D. Permeability
D
The core of a magnetic equipment uses a magnetic material with A. Least permeability B. Low permeability C. Moderate permeability D. High permeability
D
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
D
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
D
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
D
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
D
The uncharged particles which have no effect on its atomic charge. A. Nucleons B. Electrons C. Protons D. Neutrons
D
The unit of electrical energy is A. Joule B. Watt- second C. Kilowatt- hour D. All of these
D
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
D
Which of the following is a paramagnetic material? A. Carbon B. Copper C. Bismut h D. Oxygen
D
Which of the following materials has permeability slightly less than that of free space? A. Paramagnetic B. Non- magnetic C. Ferromagnetic D. Diamagnetic
D
Who demonstrated that there are magnetic effects around every current-carrying conductor and that current-carrying conductors can attract and repel each other just likemagnets? A. Luigi Galvani B. Hans Christian Oersted C. Charles Coulomb D. Andre Ampere
D
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
D