Magnetostatic Fields: Interactive Learning Quizzes for Electromagnetics

Question 1

Which of the following correctly describes the direction of magnetic field intensity (H) around a current-carrying wire?

Accepted Answer

Perpendicular to the wire

Answer

Parallel to the wire

Answer

At 45 degrees to the wire

Answer

Antiparallel to the current flow

Question 2

Ampere's circuital law relates:

Accepted Answer

Magnetic field intensity and current density

Answer

Electric field intensity and current density

Answer

Electric potential and charge density

Answer

Magnetic flux density and electric field intensity

Question 3

Which of the following boundary conditions applies to the normal component of magnetic flux density (B) at an interface between two different materials?

Accepted Answer

It is continuous

Answer

It is discontinuous

Answer

It is equal to the surface current density

Answer

It is zero

Question 4

Which of the following materials is known for its high magnetic permeability (μ)?

Accepted Answer

Iron

Answer

Copper

Answer

Aluminum

Answer

Plastic

Question 5

Which of the following is a unit vector in the direction of magnetic field intensity (H)?

Accepted Answer

a/H

Answer

a

Answer

H/a

Answer

H

Question 6

The divergence of the magnetic field intensity (H) is:

Accepted Answer

Zero

Answer

Equal to the surface charge density

Answer

Equal to the volume charge density

Answer

Proportional to the current density

Question 7

Which of the following is NOT an application of magnetostatic fields?

Accepted Answer

Capacitors

Answer

Electric motors

Answer

Loudspeakers

Answer

Transformers

Question 8

In a diagram of a magnetic field, what do field lines represent?

Accepted Answer

The direction of the magnetic field at each point

Answer

The strength of the magnetic field at each point

Answer

The magnetic flux density

Answer

Only a visual representation of the magnetic field

Question 9

How can the properties of magnetic materials be leveraged to alter and concentrate magnetic fields?

Accepted Answer

Magnetic materials with high permeability can intensify the magnetic field within a specific region by increasing its strength.

Answer

Magnetic materials can only weaken magnetic fields and cannot concentrate them.

Answer

The presence of magnetic materials has no effect on the strength or direction of magnetic fields.

Question 10

How do magnetic fields respond to changing currents?  Explain the role of inductance in this scenario.

Accepted Answer

The strength of a magnetic field is directly proportional to the rate at which current changes.

Accepted Answer

Inductance is a property that resists changes in current flow within a circuit.

Answer

Magnetic fields remain unchanged when currents vary over time.

Question 11

In a magnetic material, the relationship between magnetic field intensity (H) and magnetic flux density (B) is given by:

Accepted Answer

B = μH

Answer

H = μB

Answer

B = H/μ

Answer

H = B/μ

Question 12

Ampere's Circuital Law states that the line integral of magnetic field intensity around a closed loop is equal to:

Accepted Answer

μ₀ times the net current enclosed by the loop

Answer

ε₀ times the voltage enclosed by the loop

Answer

μ₀ times the voltage enclosed by the loop

Answer

ε₀ times the net current enclosed by the loop

Question 13

Which of the following boundary conditions applies to the normal component of magnetic flux density at the interface of two different materials?

Accepted Answer

Continuous

Answer

Zero

Answer

Proportional to the permeability difference

Answer

Discontinuous

Question 14

The inductance of a coil is given by L = μ₀N²A/l. What does the term 'A/l' in this equation represent?

Accepted Answer

The average cross-sectional area per unit length of the coil

Answer

The magnetic field strength

Answer

The total length of the coil

Answer

The number of turns in the coil

Question 15

Which of the following is the integral form of Biot-Savart's law, representing the magnetic field intensity (B) at a point due to a current-carrying wire segment?

Accepted Answer

∮_C (μ₀/4π)Idl x ŝ / r²

Answer

B = μ₀H

Answer

∮_S (B x dS) = μ₀I

Answer

∇ x B = μ₀J

Question 16

Applying Ampere's circuital law to a current-carrying loop, which equation accurately represents the relationship between the line integral of the magnetic field intensity (B) and the enclosed current (I)?

Accepted Answer

∮_C B⋅dl = μ₀I

Answer

∇ x B = μ₀(J + ϵ₀∂E/∂t)

Answer

B = μ₀(H - M)

Answer

∮_C B⋅dl = μ₀ϵ₀I / c²

Question 17

A toroid, characterized by N turns, a mean radius of R, and carrying a current I, produces a magnetic field intensity (H) inside the toroid. Which expression accurately represents this magnetic field intensity?

Accepted Answer

H = (N/2πR)I

Answer

H = (N²I² / 2πR)

Answer

H = (I²N / 2πR)

Answer

H = (N³I / 2πR)

Question 18

The magnetic energy (W) stored in a volume (V) is given by which of the following expressions?

Accepted Answer

W = ∫_V (B² / 2μ₀) dV

Answer

W = ∫_S (B ⋅ dS) / μ₀

Answer

W = ∫_V (E² / 2μ₀) dV

Answer

W = ∫_V (H² / 2ϵ₀) dV

Question 19

Which material exhibits a negative magnetic susceptibility, implying its tendency to oppose an applied magnetic field?

Accepted Answer

Diamagnetic

Answer

Ferromagnetic

Answer

Paramagnetic

Answer

Antiferromagnetic

Question 20

The Lorentz force (F) experienced by a moving point charge (q) in a magnetic field (B) is expressed as:

Accepted Answer

F = q(v x B)

Answer

F = qB²v

Answer

F = q(v dot B)

Answer

F = qBv²

Question 21

The standard unit for measuring magnetic flux density is:

Accepted Answer

Tesla

Answer

Weber

Answer

Ampere

Answer

Henry

Question 22

The divergence of the magnetic flux density (B), represented by the mathematical expression ∇⋅B, is equal to:

Accepted Answer

Zero

Answer

μ₀

Answer

ϵ₀

Answer

J

Question 23

Ampere's circuital law can be used to determine the magnetic field of a current-carrying solenoid.

Accepted Answer

True

Answer

False

Answer

Only if the solenoid has a uniform current distribution

Answer

Only if the solenoid is infinitely long

Question 24

Which of the following materials is NOT magnetic?

Accepted Answer

Copper

Answer

Iron

Answer

Cobalt

Answer

Nickel

Question 25

Which of the following applications of magnetostatic fields is used in electric motors?

Accepted Answer

Force on a current-carrying conductor in a magnetic field

Answer

Magnetic resonance imaging

Answer

Magnetic levitation

Question 26

According to Maxwell's equations, what is the divergence of the magnetic field intensity (H)?

Accepted Answer

Zero

Answer

Equal to the charge density

Answer

Equal to the displacement current

Answer

Equal to the current density

Question 27

Ampere's circuital law states that the line integral of the magnetic field intensity (H) around a closed loop is equivalent to what quantity?

Accepted Answer

The total current passing through the loop.

Answer

The total electric field enclosed by the loop.

Answer

The total magnetic flux enclosed by the loop.

Answer

The total charge enclosed by the loop.

Question 28

A circular loop with a radius of 0.1 meters carries a current of 5 Amperes. Determine the magnetic field intensity at the center of this loop.

Accepted Answer

100π μT

Answer

200π μT

Answer

50π μT

Answer

400π μT

Question 29

Which material exhibits the highest magnetic permeability among the following options?

Accepted Answer

Iron

Answer

Copper

Answer

Silver

Answer

Aluminum

Question 30

What is the formula for the energy stored within a magnetic field?

Accepted Answer

1/2LI^2

Answer

1/2LI

Answer

LI^2

Answer

LI

Question 31

A charged particle moves perpendicularly to a uniform magnetic field. Describe the force experienced by the particle.

Accepted Answer

The particle will experience a force perpendicular to both its velocity and the magnetic field.

Answer

The particle will experience no force.

Answer

The particle will experience a force in the direction of the magnetic field.

Answer

The particle will experience a force in the opposite direction of the magnetic field.

Question 32

A rectangular loop of wire is placed within a uniform magnetic field. Under what condition is the magnetic flux through the loop maximized?

Accepted Answer

Perpendicular to the magnetic field.

Answer

At 45° to the magnetic field.

Answer

The orientation of the loop does not affect the magnetic flux.

Answer

Parallel to the magnetic field.

Question 33

Ampere's circuital law states that the line integral of the magnetic field intensity (H) around a closed path is equal to what quantity?

Accepted Answer

The total current enclosed by the path.

Answer

The magnetic flux through the path.

Answer

Zero.

Answer

The total charge enclosed by the path.

Question 34

A circular loop of wire with a radius (r) of 10 cm carries a current (I) of 2 A. Determine the magnetic field intensity (H) at the center of the loop.

Accepted Answer

H = (I / (2πr)) = (2 A) / (2π * 0.1 m) = 125.664 A/m

Answer

H = (I / (4πr)) = (2 A) / (4π * 0.1 m) = 15.92 A/m

Answer

H = 0 A/m

Answer

H = (2πr / I) = (2π * 0.1 m) / (2 A) = 31.42 rad/A

Question 35

A magnetic field (B) is directed perpendicular to a plane surface. The magnetic flux density is B = 0.5 T, and the area of the surface is A = 0.2 m². Calculate the magnetic flux (Φ) through the surface.

Accepted Answer

Φ = B * A = (0.5 T) * (0.2 m²) = 0.1 Wb

Answer

Φ = B / A = (0.5 T) / (0.2 m²) = 2.5 T/m²

Answer

Φ = A / B = (0.2 m²) / (0.5 T) = 0.4 m²/T

Answer

Φ = 0.25 Wb

Question 36

A magnetic field line is a line that is:

Accepted Answer

Tangent to the direction of the magnetic field (B) at every point.

Answer

Parallel to the direction of the magnetic field (B) at every point.

Answer

Perpendicular to the direction of the magnetic field (B) at every point.

Question 37

The magnetic field intensity (H) at a point due to a current element is:

Accepted Answer

Directly proportional to the current (I) and the length (dl) of the element and inversely proportional to the square of the distance (r) from the element.

Answer

Directly proportional to the current (I) and inversely proportional to the distance (r) from the element.

Question 38

The magnetic field (B) inside a long, straight solenoid is:

Accepted Answer

Uniform and parallel to the axis of the solenoid.

Answer

Non-uniform and perpendicular to the axis of the solenoid.

Answer

Uniform and perpendicular to the axis of the solenoid.

Answer

Non-uniform and parallel to the axis of the solenoid.

Question 39

A magnetic dipole moment is created by:

Accepted Answer

A current loop.

Answer

A changing electric field.

Answer

A stationary charge.

Answer

A uniform magnetic field.

Question 40

A magnetic field (B) exerts a force (F) on a moving charge (q). This force is:

Accepted Answer

Perpendicular to both the velocity (v) of the charge and the magnetic field (B).

Answer

Parallel to the velocity (v) of the charge and perpendicular to the magnetic field (B).

Answer

Parallel to both the velocity (v) of the charge and the magnetic field (B).

Question 41

Determine the magnetic field intensity H at a distance 'r' from an infinitely long, straight wire carrying a current 'I'.

Accepted Answer

H = (I / (2πr))

Answer

H = 0

Answer

H = (2πr / I)

Answer

H = (I / (4πr))

Question 42

A current loop of radius 'a' carries a current 'I'. Calculate the magnetic field intensity H at the center of the loop.

Accepted Answer

H = (I / (2a))

Answer

H = 0

Answer

H = (2I / a)

Answer

H = (I / (4a))

Question 43

An infinitely long solenoid with 'n' turns per unit length carries a current 'I'. What is the magnetic field intensity (H) inside the solenoid?

Accepted Answer

H = nI

Answer

H = 2nI

Answer

H = nI / 2

Answer

H = I / n

Question 44

Which type of material exhibits the highest magnetic permeability?

Accepted Answer

Ferromagnetic materials

Answer

Diamagnetic materials

Answer

Superconductors

Answer

Paramagnetic materials

Question 45

A toroid with N turns and a mean radius 'r' carries a current 'I'. What is the magnetic field intensity (H) inside the toroid?

Accepted Answer

H = NI / (2πr)

Answer

H = (2πr / N) * I

Answer

H = 2πr / NI

Answer

H = NI / (4πr)

Question 46

At the interface between two magnetic materials, which boundary conditions must be satisfied?

Accepted Answer

The normal component of the magnetic flux density (B_n) is continuous, and the tangential component of the magnetic field intensity (H_t) is continuous.

Answer

The normal component of the magnetic flux density (B_n) is zero, and the normal component of the magnetic field intensity (H_n) is zero.

Answer

The tangential component of the magnetic flux density (B_t) is zero, and the tangential component of the magnetic field intensity (H_t) is zero.

Answer

The tangential component of the magnetic flux density (B_t) is continuous, and the normal component of the magnetic field intensity (H_n) is continuous.

Question 47

What is the inductance (L) of an air-core inductor with N turns, length 'l', and cross-sectional area 'A'?

Accepted Answer

L = (μ₀N²A / l)

Answer

L = (μ₀NA² / l)

Answer

L = (l / μ₀N²A)

Answer

L = (l / μ₀NA²)

Question 48

A current-carrying wire is placed near a magnetic compass. How will the compass needle behave?

Accepted Answer

The compass needle will align itself with the magnetic field lines created by the current-carrying wire.

Answer

The compass needle will move perpendicular to the direction of the magnetic field.

Answer

The compass needle will remain stationary.

Question 49

Which of the following applications directly utilizes the principles of magnetostatic fields?

Accepted Answer

Magnetic Resonance Imaging (MRI)

Answer

Transistors

Answer

Solar panels

Answer

Photovoltaic cells