Electrical Engineering · Question Bank

Magnetic Circuits

84 questions · page 1 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
#1📜 EE Pre-Board August 2012📘 PowerhouseEasy
The unit of retentivity is
AAmpere turn
Bampere turn/weber
Campere turn/meter
Ddimensionless
#2📜 EE Pre-Board August 2012📘 PowerhouseEasy
The ratio of the total flux to useful flux is called _.
AMutual flux
BFlux Factor
CLeakage Factor
DMagnetic Factor
#3📜 EE Pre-Board August 2012📘 PowerhouseEasy
The process by which metallic parts are demagnetized is called
Adegreasing
Bdegaussing
Cdegrading
Ddemagnetizing
#4📜 EE Pre-Board August 2012📘 PowerhouseEasy
What is the force between two wires carrying currents 10 and 50 A each? The lengths of the wires are 50 cm and are separated by 5 cm distance.
A0.005 N
B0.002 N
C0.001 N
D0.004 N
#5📜 EE Pre-Board August 2012📘 PowerhouseEasy
The area of hysteresis loop is the measure of
Apermittivity
Bpermeance
Cenergy loss per cycle
Dmagnetic flux
#6📜 EE Pre-Board August 2012📘 PowerhouseEasy
A magnetizing force of 1000 AT/m will produce a flux density of _ in air.
A0.63 mWb/m²
B0.63 Wb/m³
C1.257 mWb/m³
D1.257 Wb/m³
#7📜 EE Pre-Board August 2012📘 PowerhouseEasy
The greater percentage of materials are _ .
ADiamagnetic
BParamagnetic
CFerromagnetic
DNon- magnetic
#8📜 EE Pre-Board August 2012📘 PowerhouseMedium
An iron ring 100 cm mean circumference is made from round iron of cross section \(10^{-3}\) m². Its relative permeability is 500. If it is wound with 250 turns, what current will be required to produce a flux of \(2 \times 10^{-3}\) Wb?
A21.47 A
B14.27 A
C12.74 A
D17.42 A
#9📜 EE Pre-Board August 2012📘 PowerhouseEasy
One ampere-turn is equivalent to _ gilberts.
A1.16
B1.26
C1.36
D1.46
#10📜 EE Pre-Board March 2013📘 PowerhouseEasy
Which of the following is a vector quantity?
AMagnetic Flux
BMagnetic flux density
CMagnetic reluctance
DMagnetic field intensity
#11📜 EE Pre-Board March 2013📘 PowerhouseEasy
A current of 10 A is flowing in a flexible conductor of length 1.5 m. A force of 15 N acts on it when it is placed in a uniform field of 2 T. Calculate the angle between the magnetic field and the direction of the current.
A30°
B45°
C60°
D90°
#12📜 EE Pre-Board March 2013📘 PowerhouseEasy
A magnetic field exists around
ACopper
BIron
CMoving charges
DAluminum
#13📜 EE Pre-Board March 2013📘 PowerhouseEasy
Ten oersted is equivalent to
A10 Gb/m
B1 Gb/m
C10 Gb/cm
D100 Gb/cm
#14📜 EE Pre-Board March 2013📘 PowerhouseEasy
Calculate the magnetic field intensity to produce a flux density of \(10 \times 10^{-3}\) tesla at the center of a long straight solenoid.
A6,423 AT/m
B7,958 AT/m
C8,323 AT/m
D7,869 AT/m
#15📜 EE Pre-Board March 2013📘 PowerhouseMedium
Determine the inductance L of a coil of 500 turns wound on an air cored torroidal ring having a mean diameter of 300mm. The ring has a circular cross section of diameter 50mm.
A\(6.54 \times 10^{-3}\) H
B\(6.54 \times 10^{-4}\) H
C\(3.27 \times 10^{-3}\) H
D\(3.27 \times 10^{-4}\) H
#16📜 EE Pre-Board March 2013📘 PowerhouseEasy
Permeance is analogous to
AConductance
BResistance
CReluctance
DInductance
#17📜 EE Pre-Board August 2013📘 PowerhouseHard
An iron ring of circular cross-section of \(5 \times 10^{-4}\) m² has a mean circumference of 2 m. It has a saw-cut of \(2 \times 10^{-3}\) m length and is wound with 800 turns of wire. Determine the exciting current when the flux in the air gap is \(0.5 \times 10^{-3}\) Wb. Given μr of iron = 600 and leakage factor = 1.2. Assume the areas of air gap and iron are the same.
A2.95 A
B3.95 A
C4.95 A
D5.95 A
#18📜 EE Pre-Board August 2013📘 PowerhouseEasy
Two straight parallel wires 2 m long and 3 mm apart carry a current of 8 A in opposite directions. Calculate the force between these conductors.
A\(8.25 \times 10^{-3}\) N
B\(8.75 \times 10^{-3}\) N
C\(8.33 \times 10^{-3}\) N
D\(8.53 \times 10^{-3}\) N
#19📜 EE Pre-Board August 2013📘 PowerhouseEasy
An air cored coil has 500 turns. The mean length of magnetic flux path is 50 cm and the area of cross-section is \(5 \times 10^{-4}\) m² . If the exciting current is 5 A, determine the flux density.
A\(3.1415 \times 10^{-3}\) T
B\(3.1415 \times 10^{-4}\) T
C\(6.283 \times 10^{-3}\) T
D\(6.283 \times 10^{-4}\) T
#20📜 EE Pre-Board March 2014📘 PowerhouseEasy
What is the counterpart of magnetic flux in an electric circuit?
Avoltage
Bcurrent
Cresistance
Dconductance

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