Electrical Engineering · Question Bank

Magnetic Circuits

84 questions · page 4 of 5. Answer in your head first, then check the solution.

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TypeAll 84Problem solving 28Objective 56
DifficultyAll 84Easy 78Medium 5Hard 1
#61📘 EE Pocket Reviewer RojasEasy
A magnetic material whose relative permeability is much greater than 1.
AFerromagnetic material
BParamagnetic material
CDiamagnetic material
DSuper magnetic material
#62📘 EE Pocket Reviewer RojasEasy
What is the purpose of the air gap in the iron core of an inductor?
AIt will prevent the core to saturate
BIt will decrease the hysteresis loss
CIt will prevent the flux to change
DIt will decrease the wattage loss of the coil
#63📘 EE Pocket Reviewer RojasEasy
Which of the following is a non-magnetic material?
ACobalt
BNickel
CAluminum
DGadolinium
#64📘 EE Pocket Reviewer RojasEasy
Which of the following is the eddy current loss directly proportional?
AAverage flux density
BSquare of the maximum flux density
CThickness of the core lamination
DFrequency of the current in the coil
#65📘 EE Pocket Reviewer RojasEasy
What is the reciprocal of permeance?
AConductance
BAmpere-turns
CReluctance
DFlux density
#66📘 EE Pocket Reviewer RojasEasy
MMF in magnetic circuit is similar to which one in electric circuits?
AVoltage source
BCurrent
CVoltage drop
DResistance
#67📘 EE Pocket Reviewer RojasEasy
What is the SI unit of permeability?
AHenry
BUnitless
C1/ Henry
DHenry/meter
#68📘 EE Pocket Reviewer RojasEasy
How does an inductor works?
ABy choking off dc
BBy charging a piece of wire
CBy storing energy as a magnetic field
DBy introducing resistance into a circuit
#69📘 EE Pocket Reviewer RojasEasy
Which one will not make the flux density in the material to saturate?
ASoft iron
BAir
CCobalt steel
DSilicon steel
#70📘 EE Pocket Reviewer RojasEasy
What is the relative permeability of a paramagnetic material?
AExactly equal to 1
BSlightly less than 1
CSlightly greater than 1
DMuch greater than 1
#71📘 EE Pocket Reviewer RojasEasy
A bar magnet is divided into two pieces. Which one is true?
AThere is an electric repulsive force between the broken pieces
BThere is an electric attractive force between the broken pieces
CThere is a magnetic repulsive force between the. broken pieces
DThere is a magnetic attractive force between the broken pieces
#72📘 EE Pocket Reviewer RojasEasy
Magnetic field lines determines which of the following?
AOnly the direction of the field
BOnly the shape of the field
CThe relative strength of the field
DBoth the direction and relative strength of the field
#73📘 EE Pocket Reviewer RojasEasy
Which one is a significant advantage of a toroidal coil over a solenoid?
AThe toroid is easier to wind
BThe solenoid cannot carry as much current
CThe toroid is easier to tune
DThe magnetic flux in a toroid is practically all within the core
#74📘 EE Pocket Reviewer RojasEasy
What is the relative permeability of a diamagnetic material?
AExactly equal to 1
BSlightly less than 1
CSlightly greater than 1
DMuch greater than 1
#75📘 EE Pocket Reviewer RojasEasy
At an audio frequency range (about 20 Hz to 20 kHz), what type of inductors is commonly used?
AAir-core
BToroidal
CSolenoid
DReactor
#76📘 EE Pocket Reviewer RojasEasy
What do you mean by permeability?
APower a piece of metal has on a magnet
BPower found in a transformer core
CPower found in an electromagnet
DEase in which metals may become magnetized
#77📘 EE Pocket Reviewer RojasEasy
How can the hysteresis loss in a magnetic core be reduced?
ALaminate the core
BIncrease the frequency of the excitation current
CUse grain-oriented silicon steel core
DUse a solid iron core
#78📘 EE Pocket Reviewer RojasEasy
Which of the following element stores energy in the electromagnetic field?
ACapacitor
BImpedance
CResistor
DInductor
#79📘 EE Pocket Reviewer RojasEasy
Permeance in a magnetic circuit is ____ the cross section area of the magnetic path.
ADirectly proportional to
BInversely proportional to
CDirectly proportional to the square of
DInversely proportional to the square of
#80📘 EE Pocket Reviewer RojasEasy
A bar magnet has how many poles?
ATwo poles
BFour poles
CNo poles
DOne pole

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