Electromagnetism: Master the Fundamentals for Electrical Engineering

Question 1

Which of Maxwell's equations relates the curl of the magnetic field to the displacement current and conduction current?

Accepted Answer

Ampere's circuital law with Maxwell's addition

Answer

Gauss's law for electric fields

Answer

Faraday's law of induction

Answer

Gauss's law for magnetic fields

Question 2

Which of the following is NOT one of Maxwell's four fundamental equations?

Accepted Answer

Gauss's law for magnetic fields

Answer

Gauss's law for electric fields

Answer

Faraday's law of induction

Answer

Ampère's circuital law with Maxwell's addition

Question 3

Which Maxwell equation describes the relationship between the divergence of the electric field and the electric charge density?

Accepted Answer

∇ · D = ρ/ε₀

Answer

∇ × E = -μ₀J

Answer

∇ × H = J + ∂D/∂t

Answer

∇ · B = 0

Question 4

Which of the following is not one of Maxwell's equations?

Accepted Answer

Ohm's law

Answer

Gauss's law for electric fields

Answer

Ampère's circuital law with Maxwell's addition

Answer

Faraday's law of induction

Question 5

Which Maxwell's equation describes the relationship between a changing magnetic field and an electric field?

Accepted Answer

Faraday's law

Answer

Gauss's law

Answer

Ampère's circuital law

Answer

Lenz's law

Question 6

Which Maxwell's equation describes the relationship between the changing magnetic field and the curl of the electric field?

Accepted Answer

Faraday's Law of Induction

Answer

Gauss's Law for Electric Fields

Answer

Ampère's Circuital Law with Maxwell's Addition

Answer

Gauss's Law for Magnetic Fields

Question 7

According to Faraday's Law, the electromotive force (EMF) induced in a coil is directly proportional to the:

Accepted Answer

Rate of change of magnetic flux through the coil

Answer

Current in the coil

Answer

Area of the coil

Answer

Resistance of the coil

Question 8

Which property is unique to electromagnetic waves?

Accepted Answer

They can travel through a vacuum.

Answer

They are longitudinal waves.

Answer

Their speed in a material is always faster than the speed of light in a vacuum.

Answer

They are not affected by magnetic fields.

Question 9

Which Maxwell's equation relates the electric field to the magnetic field?

Accepted Answer

Faraday's law of induction

Answer

Gauss's law for electric fields

Answer

Gauss's law for magnetic fields

Answer

Ampère's circuital law

Question 10

Which of the following is NOT a fundamental Maxwell's equation?

Accepted Answer

Gauss's law for magnetic fields

Answer

Gauss's law for electric fields

Answer

Faraday's law of induction

Answer

Ampère's circuital law with Maxwell's addition

Question 11

Which Maxwell's equation explicitly relates the divergence of the electric field to the electric charge density?

Accepted Answer

∇ · D = ρ

Answer

∇ × E = - ∂B/∂t

Answer

∇ · B = 0

Answer

∇ × H = J + ∂D/∂t

Question 12

Which of Maxwell's equations expresses the relationship between the divergence of the electric field and the electric charge density?

Accepted Answer

$
abla cdot mathbf{E} = rac{ho}{varepsilon_0}$

Answer

$
abla cdot mathbf{B} = 0$

Answer

$
abla 	imes mathbf{H} = mathbf{J}_f + rac{partial mathbf{D}}{partial t}$

Answer

$
abla 	times mathbf{E} = -rac{partial mathbf{B}}{partial t}$

Question 13

Which Maxwell's equation relates electric field, magnetic field, and electric current?

Accepted Answer

Ampère's circuital law

Answer

Gauss's law for electric fields

Answer

Gauss's law for magnetic fields

Answer

Faraday's law of induction

Question 14

An electric field varies with time as E(t) = E0 * sin(ωt), where E0 and ω are constants. Which of Maxwell's equations does this time-varying electric field satisfy?

Accepted Answer

Faraday's Law

Answer

Gauss's Law

Question 15

Which equation is not part of Maxwell's equations?

Accepted Answer

Ohm's law

Answer

Gauss's law

Answer

Faraday's law

Answer

Ampère's circuital law

Question 16

According to Lenz's Law, when the magnetic flux through a coil increases, what is the direction of the induced current in the coil?

Accepted Answer

Opposes the change in magnetic flux

Answer

Aligns with the change in magnetic flux

Answer

Perpendicular to the plane of the coil

Question 17

According to Lenz's Law, the direction of induced current in a conducting loop is primarily determined by its opposition to changes in which fundamental quantity?

Accepted Answer

Magnetic flux

Answer

Electric charge

Answer

Current flow

Answer

Voltage magnitude

Question 18

In a region of space where a uniform electric field **E** exists, what is the relationship between the divergence of **E** and the electric charge distribution in that region?

Accepted Answer

The divergence of **E** is directly proportional to the electric charge density in the region.

Answer

The divergence of **E** is always zero, regardless of the charge distribution.

Answer

The divergence of **E** is always positive, indicating the presence of positive charges only.

Answer

The divergence of **E** is independent of the strength of the electric field.

Question 19

A capacitor with a capacitance of 10 µF is connected to a battery with a voltage of 100 V. What is the energy stored in the capacitor?

Accepted Answer

0.05 J

Answer

1 J

Answer

10 J

Question 20

Which Maxwell's equation describes electromagnetic induction?

Accepted Answer

∇×E = -∂B/∂t

Answer

∇⋅D = ρ

Answer

∇⋅B = 0

Answer

∇×H = J

Question 21

Which of the following is not one of Maxwell's equations?

Accepted Answer

Ohm's law

Answer

Gauss's law for electric fields

Answer

Faraday's law of induction

Question 22

According to Faraday's law of electromagnetic induction, the induced electromotive force (EMF) in a conductor is directly proportional to the:

Accepted Answer

Rate of change of magnetic flux

Answer

Steady magnetic field strength

Answer

Material properties of the conductor

Answer

Cross-sectional area of the conductor

Question 23

An inductor has an inductance of L. According to Faraday's law, what is the electromotive force (EMF) induced in the inductor when the current (I) flowing through it changes at a rate of dI/dt?

Accepted Answer

EMF = - L * (dI/dt)

Answer

EMF = - L * I

Answer

EMF = L * I * (dI/dt)

Answer

EMF = (dI/dt) / L

Question 24

What is the primary significance of Maxwell's equations in electromagnetism?

Accepted Answer

They provide a comprehensive mathematical framework for describing all classical electromagnetic phenomena.

Answer

They are only valid for static electric and magnetic fields.

Answer

They are only applicable to certain materials.

Answer

They are primarily used for theoretical research with no practical applications.

Question 25

Which of Maxwell's equations explains how a changing magnetic field creates an electric field?

Accepted Answer

Faraday's law of induction

Answer

Gauss's law for electric fields

Answer

Ampère's circuital law with Maxwell's addition

Answer

Gauss's law for magnetic fields

Question 26

Which Maxwell's equation describes the relationship between the curl of the electric field (E) and the changing magnetic field (B) over time?

Accepted Answer

∇×E = -∂B/∂t

Answer

∇⋅B = 0

Answer

∇⋅E = ρ/ε0

Question 27

Which Maxwell's equation describes Faraday's Law of Induction, which relates the change in magnetic field to the electric field?

Accepted Answer

Faraday's Law of Induction: ∇ × E = -∂B/∂t

Answer

Gauss's Law: ∇ ⋅ E = ρ/ε₀

Answer

Ampère's Circuital Law with Maxwell's addition: ∇ × B = μ₀(J + ε₀∂E/∂t)

Question 28

Which property is NOT fundamental to an electromagnetic field?

Accepted Answer

Conductivity

Answer

Electric field intensity

Answer

Magnetic flux density

Answer

Polarization

Question 29

Which material exhibits nonlinear magnetic behavior?

Accepted Answer

Ferrite

Answer

Vacuum

Answer

Air

Answer

Aluminum

Question 30

The displacement current in a capacitor is:

Accepted Answer

Proportional to the rate of change of electric field

Answer

Equal to the conduction current

Answer

Zero

Answer

Opposite in direction to the conduction current

Question 31

The skin effect occurs in:

Accepted Answer

Good conductors at high frequencies

Answer

Poor conductors at low frequencies

Answer

Good insulators at high frequencies

Answer

Poor insulators at low frequencies

Question 32

The Brewster angle is the angle of incidence at which:

Accepted Answer

Partially reflected and transmitted waves have equal amplitudes

Answer

Total internal reflection occurs

Answer

The reflected wave is completely linearly polarized

Answer

The transmitted wave is completely circularly polarized

Question 33

Gauss's law relates:

Accepted Answer

Electric flux to electric charge

Answer

Electric field to electric charge

Answer

Magnetic field to magnetic charge

Answer

Magnetic flux to magnetic charge

Question 34

The displacement current is a phenomenon that arises due to:

Accepted Answer

A changing electric field

Answer

A changing magnetic field

Answer

The flow of charges in a dielectric material

Answer

The flow of charges in a conductor

Question 35

A transformer is an electrical device that:

Accepted Answer

Transfers electrical energy between circuits using magnetic coupling

Answer

Converts electrical energy into mechanical energy

Answer

Stores electrical energy in a capacitor

Answer

Amplifies electrical signals

Question 36

The skin effect refers to the tendency of:

Accepted Answer

High-frequency currents to concentrate near the surface of a conductor

Answer

The resistance of a conductor to increase with increasing current

Answer

The capacitance of a capacitor to decrease with increasing frequency

Answer

The inductance of an inductor to increase with increasing frequency

Question 37

A material with low electrical conductivity is known as a:

Accepted Answer

Insulator

Answer

Conductor

Answer

Semiconductor

Answer

Superconductor

Question 38

The Poynting vector in electromagnetism represents:

Accepted Answer

Power density of an electromagnetic field

Answer

Electric field strength of an electromagnetic field

Answer

Magnetic field strength of an electromagnetic field

Answer

Energy density of an electromagnetic field

Question 39

A waveguide is a device used for:

Accepted Answer

Transmitting electromagnetic waves through a confined space

Answer

Generating electromagnetic waves

Answer

Detecting electromagnetic waves

Answer

Amplifying electromagnetic waves

Question 40

Which of the following Maxwell's equations relates electric displacement to bound charges?

Accepted Answer

Gauss's law: ∇⋅D = ρ_b

Answer

Gauss's law: ∇⋅B = 0

Answer

Faraday's law: ∇×E = -∂B/∂t

Answer

Ampère's circuital law with Maxwell's addition: ∇×B = μ0(J + ∂D/∂t)

Question 41

The skin effect in conductors refers to:

Accepted Answer

Current concentrated near the conductor's surface

Answer

Current evenly distributed throughout the conductor

Answer

Current forming a spiral pattern within the conductor

Answer

Current flowing non-uniformly within the conductor

Question 42

A key distinction between electric and magnetic fields is:

Accepted Answer

Electric fields arise from charges and currents, while magnetic fields only arise from currents

Answer

Magnetic fields arise from charges and currents, while electric fields only arise from charges

Answer

Electric fields exist only around stationary charges, while magnetic fields exist around both stationary and moving charges

Answer

Magnetic fields exist only around moving charges, while electric fields exist around both stationary and moving charges

Question 43

The Poynting vector is primarily used to calculate:

Accepted Answer

Power flow in an electromagnetic field

Answer

EMF induced in a conductor

Answer

Force on a charged particle

Answer

Energy stored in an electromagnetic field

Question 44

Inductance of a coil is directly proportional to:

Accepted Answer

Number of coil turns

Answer

Coil's cross-sectional area

Answer

Coil's length

Answer

Core material

Question 45

A capacitor stores energy primarily in the form of:

Accepted Answer

Electric field

Answer

Magnetic field

Answer

Mechanical energy

Answer

Chemical energy

Question 46

To minimize eddy currents in transformers, which method is commonly employed?

Accepted Answer

Laminated core construction

Answer

Solid core construction

Answer

Increasing AC supply frequency

Answer

Reducing the number of winding turns

Question 47

In high-frequency applications, why are lumped-element models for transmission lines less accurate, and how do distributed-element models overcome these limitations?

Accepted Answer

At high frequencies, the inductance and capacitance of the transmission line become distributed along its length, making the lumped-element model less accurate.

Answer

The resistance of the transmission line becomes negligible at high frequencies.

Answer

Distributed-element models are always more accurate than lumped-element models.

Answer

Lumped-element models are only applicable for DC circuits.

Question 48

Which waveguide characteristic primarily governs the number of modes it can support?

Accepted Answer

Cross-sectional shape

Answer

Length

Answer

Material properties

Answer

Frequency

Question 49

How do metamaterials achieve negative permittivity and permeability, and what are the potential applications of these properties in advanced optical devices?

Accepted Answer

Metamaterials manipulate permittivity and permeability through resonant structures that interact with electromagnetic waves.

Answer

Metamaterials inherently possess negative permittivity and permeability due to their unique molecular composition.

Answer

The negative permittivity and permeability of metamaterials stem from the presence of exotic materials with unusual electronic structures.

Answer

Metamaterials are unsuitable for advanced optical devices due to their high losses.

Question 50

In electromagnetism, the fundamental concept that describes the property of matter to exert or experience an electrostatic force is:

Accepted Answer

Electric charge

Answer

Magnetic field

Answer

Voltage

Answer

Resistance

Question 51

Maxwell's equations are a set of mathematical equations that describe:

Accepted Answer

The behavior of electromagnetic fields

Answer

The propagation of mechanical waves

Answer

The principles of quantum mechanics

Answer

The flow of fluids

Question 52

Which of the following applications of electromagnetism is NOT found in electrical engineering?

Accepted Answer

Internal combustion engines

Answer

Electric motors

Answer

Transformers

Answer

Transistors

Question 53

The shape of the magnetic field around a long, straight wire carrying electric current is:

Accepted Answer

Circular

Answer

Elliptical

Answer

Parabolic

Answer

Hyperbolic

Question 54

The SI unit of electric potential is the:

Accepted Answer

Volt

Answer

Ampere

Answer

Tesla

Answer

Ohm

Question 55

In the context of an electromagnetic plane wave, the relationship between the electric field E and magnetic field H is that:

Accepted Answer

E is perpendicular to H

Answer

E is parallel to H

Answer

E is proportional to H

Answer

E is inversely proportional to H

Question 56

An electronic device used for converting alternating current (AC) to direct current (DC) is a:

Accepted Answer

Rectifier

Answer

Capacitor

Answer

Resistor

Answer

Inductor

Question 57

Gauss's law for magnetism states that:

Accepted Answer

The net magnetic flux through any closed surface is zero

Answer

The electric field at a point is proportional to the charge at that point

Answer

The potential energy of a point charge is proportional to its distance from another point charge

Answer

The magnetic force between two current-carrying wires is proportional to the product of their currents

Question 58

'Skin effect' in electromagnetism refers to:

Accepted Answer

The tendency for high-frequency currents to distribute near the surface of a conductor

Answer

The influence of magnetic fields on current flow within a conductor

Answer

The increase in resistance of a conductor due to an electric field

Answer

The decrease in capacitance of a capacitor due to a magnetic field

Question 59

Which of the following is not a fundamental quantity in electromagnetism?

Accepted Answer

Voltage

Answer

Electric charge

Answer

Magnetic field intensity

Answer

Electric current

Question 60

In a lossless transmission line, which parameters determine the characteristic impedance?

Accepted Answer

Inductance and capacitance

Answer

Resistance and capacitance

Answer

Inductance and resistance

Answer

Capacitance and conductance

Question 61

Which device operates based on the principle of electromagnetic induction?

Accepted Answer

Transformer

Answer

Resistor

Answer

Capacitor

Answer

Diode

Question 62

Which mathematical tool is used to calculate the magnetic field?

Accepted Answer

Vector potential

Answer

Scalar potential

Answer

Electric potential

Answer

Magnetic flux density

Question 63

Which property of the electric displacement vector is related to electric charge density?

Accepted Answer

Divergence

Answer

Curl

Answer

Gradient

Answer

Laplacian

Question 64

Which boundary condition ensures the continuity of the normal component of electric flux density across an interface?

Accepted Answer

Cauchy condition

Answer

Dirichlet condition

Answer

Neumann condition

Answer

Mixed condition