field gloassary

1. Fundamentals of Field Theory & Vector Calculus

Term	Definition	Year of Appearance
Field	A spatial distribution of a scalar or vector quantity, which may or may not be a function of time.	2024
Quasi-static conditions	Conditions under which the time-varying effects of electromagnetic fields are slow enough that static field approximations remain mathematically valid.	2020
Metric coefficient	A scale factor ($h_i$) in orthogonal coordinate systems that relates the differential change in a coordinate variable to the actual physical differential length ($d{l}_i=h_{i}d{u}_i$).	2019
Homogeneous medium	A medium whose material properties (permittivity $ϵ$, permeability $\mu$, and conductivity $\sigma$) are uniform and do not change from point to point in space.	2024, 2023, 2019, 2017, 2015
Linear medium	A medium where its electromagnetic response (like $\vec{D}$ or $\vec{B}$) is directly proportional to the applied field (like $\vec{E}$ or $\vec{H}$), obeying superposition.	2024, 2023, 2017, 2015
Isotropic medium	A medium whose material properties are the same in all directions, meaning $ϵ$, $\mu$, and $\sigma$ are scalar quantities rather than tensors.	2024, 2023, 2017, 2015
Gradient	A vector operation on a scalar field that represents both the magnitude and the direction of the maximum space rate of increase of that scalar.	Foundational (L2 Notes)
Divergence	A vector operation that determines the net outward flux or dispersion of a vector field from a specific infinitesimally small volume.	Foundational (L2 Notes)
Curl	A vector operation that determines the rotation or circulation of a vector field around a point.	2022
Gaussian surface	A hypothetical closed surface chosen symmetrically around a charge distribution to easily evaluate electric flux and electric field intensity using Gauss’s law.	Foundational (CT 1)

2. Electrostatics

Term	Definition	Year of Appearance
Electric field intensity ($\vec{E}$)	The force per unit charge that a very small, stationary, positive test charge experiences when placed in a region where an electric field exists.	2021, 2019, 2016
Electric potential ($V$)	The total work done per unit positive charge in moving a charge from infinity to a specific point within an electric field.	2021, 2017, 2016
Equipotential line	A line consisting of continuous points that all share the exact same electric potential value, across which no work is required to move a charge.	2024
Electric dipole	A system consisting of two equal but opposite point charges separated by a small distance.	2024, 2019
Electric dipole moment ($\vec{p}$)	A vector quantity defined as the product of the charge magnitude and the separation distance vector, directed from the negative to the positive charge.	2023, 2021, 2016
Electrostatic energy	The potential energy stored in an electrostatic field, equivalent to the total work required to assemble a given system of charges from infinity to their final positions.	2025, 2024, 2023, 2022, 2020, 2019, 2018
Polarization vector ($\vec{P}$)	The polarization-induced dipole moment per unit volume within a dielectric material when subjected to an external electric field.	Foundational (Masuk Notes)

3. Magnetostatics

Term	Definition	Year of Appearance
Magnetic dipole	A small, closed current-carrying loop that produces a magnetic field mathematically analogous to the electric field of an electric dipole.	2017, 2015
Magnetic dipole moment ($\vec{m}$)	A vector defined as the product of the current and the loop area, with its direction determined by the right-hand rule relative to the current flow.	2018, 2016
Vector magnetic potential ($\vec{A}$)	An intermediary mathematical vector field whose curl gives the actual magnetic flux density ($\vec{B}=\nabla \times \vec{A}$), used to simplify the calculation of complex magnetic fields.	2025, 2024, 2022, 2019, 2018, 2016
Scalar magnetic potential ($V_m$)	A fictitious scalar field whose negative gradient equals the magnetic field intensity ($\vec{H}$) in a region completely free of conduction currents ($\vec{J}=0$).	2018
Magnetization vector ($\vec{M}$)	The volume density of magnetic dipole moments within a magnetic material resulting from the alignment of atomic dipoles.	2018, 2016, 2015
Magnetic susceptibility (${\chi }_m$)	A dimensionless quantity that indicates the degree to which a material becomes magnetized in response to an applied magnetic field.	2025, 2022, 2015
Magnetic field intensity ($\vec{H}$)	A vector field representing the external magnetic driving influence independent of the material, related to flux density and magnetization via $\vec{H}=\frac{\vec{B}}{{\mu }_0}-\vec{M}$.	2018, 2016
Hall effect	The phenomenon where a transverse voltage (Hall voltage) is generated across a current-carrying conductor placed in a magnetic field perpendicular to the current.	2025, 2021, 2019
Conduction current	Electric current caused by the drift motion of conduction electrons and/or holes in conductors and semiconductors, governed by Ohm’s law.	Foundational (EM Eqns)
Convection current	Electric current resulting from the macroscopic physical motion of charged particles, such as electrons or ions moving through a vacuum or a fluid.	Foundational (EM Eqns)

4. Time-Varying Fields & Maxwell’s Equations

Term	Definition	Year of Appearance
Displacement current	A fictitious current proportional to the time rate of change of the electric displacement field ($\vec{D}$), introduced by Maxwell to make Ampere’s law consistent for time-varying scenarios.	2017, 2016
Displacement current density (${\vec{J}}_d$)	The exact rate of change of the electric displacement field with respect to time ($\frac{\partial \vec{D}}{\partial t}$), which allows electromagnetic waves to propagate even in a vacuum.	2023
Retarded scalar potential	A time-varying scalar potential at a observation point that depends on the source charge density at an earlier time $(t-R/u)$, accounting for the finite propagation speed of EM waves.	Foundational (Masuk Notes)

5. Electromagnetic Waves

Term	Definition	Year of Appearance
Complex permittivity (${ϵ}_c$)	A parameter (${ϵ}^{\prime }-j{ϵ}^{\prime \prime }$) that accounts for both the material’s ability to store electric energy (real part) and its energy losses due to damping or conductivity (imaginary part).	2023, 2019
Loss tangent ($\tan \delta$)	The ratio of the imaginary part to the real part of complex permittivity (${ϵ}^{\prime \prime }/{ϵ}^{\prime }$), serving as a direct measure of power loss in a lossy dielectric medium.	2019, 2015
Intrinsic impedance ($\eta$)	The ratio of the electric field intensity ($\vec{E}$) to the magnetic field intensity ($\vec{H}$) of an electromagnetic wave traveling through a specific medium.	2023, 2022
Skin depth ($\delta$)	The specific distance a wave must travel in a good conductor for its amplitude to decay by a factor of $e^{-1}$ (or down to 36.8% of its original value).	2025, 2021, 2016
Phase velocity ($u_p$)	The velocity at which a constant phase point of a single-frequency plane wave propagates through a medium.	2024
Group velocity ($u_g$)	The velocity at which the overall envelope of a wave packet (comprising a group of frequencies) propagates, representing the speed of energy or information transfer.	2024
Dispersion	The phenomenon of signal distortion that occurs when different frequency components of a wave travel at different phase velocities in a medium.	Foundational (PEM Ch 8)
Polarization	A property describing the time-varying magnitude and orientation of the electric field vector of an electromagnetic wave as it propagates.	2025, 2024, 2023, 2021, 2019, 2017, 2016, 2015
Brewster angle	The specific angle of incidence at a dielectric interface where a parallel-polarized (P-polarized) electromagnetic wave experiences zero reflection and is perfectly transmitted.	2020

6. Radio Wave Propagation

Term	Definition	Year of Appearance
Virtual height	The apparent reflection height of an ionospheric layer calculated by assuming the radio wave traveled at the speed of light in a vacuum for its entire round trip.	2021, 2020, 2018, 2016, 2015
Skip distance	The minimum distance along the Earth’s surface from a transmitter to the point where a sky wave of a specific frequency returns to Earth.	2018, 2016, 2015
Maximum Usable Frequency (MUF)	The absolutely highest radio frequency that can be successfully used for communication between two specific points via ionospheric reflection.	2018, 2016, 2015
Minimum Usable Frequency	The lowest radio frequency that can overcome ionospheric absorption and successfully establish a communication link.	2018
Critical frequency ($f_c$)	The highest frequency that will be reflected back to Earth by an ionospheric layer when the wave is transmitted vertically upward.	2018, 2016
Plasma frequency ($f_p$)	The natural oscillation frequency of free electrons in an ionized gas, determining the boundary condition between wave reflection and wave transmission.	2021, 2018, 2016
Doppler effect	The apparent shift in the frequency of an electromagnetic wave resulting from the relative motion between the transmitter and the receiver.	2024, 2021, 2019, 2017, 2016, 2015

missed:

After performing a deep check of all 31 sources (including the syllabus, slide decks, and past year questions), I have identified several foundational terms and specific sub-classifications that were missing from the initial glossary.

Many of these terms are derived from the instructor’s specific slides (like material classifications and dispersion types) and explicitly appear in derivations or comparative questions in the PYQs.

Here are the missing terms categorized by topic:

1. Fundamentals of Field Theory & Vector Calculus

Term	Definition	Year of Appearance
Solenoidal field	A vector field that has zero divergence everywhere ($\nabla \cdot \vec{A}=0$), meaning it has no flow sources or sinks (e.g., magnetic flux lines).	Foundational (L 2)
Irrotational field	A non-zero vector field that is completely curl-free ($\nabla \times \vec{A}=0$). It flows in essentially straight lines and is also known as a conservative field.	Foundational (L 2)
Anisotropic material	A material where properties depend on direction, meaning vectors like $\vec{D}$ and $\vec{E}$ are not parallel, and permittivity $ϵ$ is a tensor.	Foundational (L 11)
Inhomogeneous material	A material whose properties (like permittivity) vary depending on the spatial coordinates (x, y, z).	Foundational (L 11)

2. Electrostatics

Term	Definition	Year of Appearance
Line / Surface / Volume Charge Density	The amount of electric charge per unit length (${\rho }_l$), per unit surface area (${\rho }_s$), or per unit volume (${\rho }_v$).	2021, 2018
Conservative field	A field (like the static electric field) where the line integral around any closed path vanishes, meaning the work done moving a charge between two points is independent of the path taken.	Foundational (L 2)

3. Magnetostatics

Term	Definition	Year of Appearance
Diamagnetism	A property of materials that exhibit no permanent magnetism; they are weakly repelled by a magnetic field and their induced magnetic moment disappears when the applied field is removed.	Foundational (L 8)
Paramagnetism	A property of materials where magnetic moments do not cancel completely, resulting in a weak, positive alignment with an applied magnetic field.	Foundational (L 8)
Ferromagnetism	A property of materials (like iron) that can possess large, permanent magnetizations even in the absence of an applied magnetic field due to aligned magnetic domains.	Foundational (L 8)
Curie Temperature ($T_c$)	The critical temperature above which a ferromagnetic or ferrimagnetic material loses its permanent magnetization and becomes paramagnetic.	Foundational (L 8)

4. Time-Varying Fields & Maxwell’s Equations

Term	Definition	Year of Appearance
Electrolytic current	Electric current that results from the migration of positive and negative ions in a fluid or electrolyte under the influence of an electric field (often grouped with conduction/convection notes).	Foundational (EM Eqns)
Retarded vector potential	A time-varying vector magnetic potential that accounts for the finite propagation speed of waves, depending on current density at a delayed time $(t-R/u)$.	Foundational (EM Eqns)

5. Electromagnetic Waves

Term	Definition	Year of Appearance
Good conductor	A medium where the conductivity is much greater than the product of angular frequency and permittivity ($\sigma \gg \omega ϵ$), causing EM waves to be heavily attenuated or reflected.	2023, 2017, 2015
Lossy dielectric	A medium acting as a good insulator where conductivity is very low ($\sigma \ll \omega ϵ$), allowing wave propagation with minimal attenuation and deep penetration.	2023, 2017, 2015
Transverse Electromagnetic (TEM) Wave	An electromagnetic wave where both the electric field ($E$) and magnetic field ($H$) are entirely perpendicular to each other and to the direction of propagation.	Foundational (L 12)
P-Polarization (Parallel)	A special case of oblique incidence where the electric field ($\vec{E}$) vector is entirely parallel to the plane of incidence.	Foundational (L 15)
S-Polarization (Perpendicular)	A special case of oblique incidence where the electric field ($\vec{E}$) vector is strictly perpendicular to the plane of incidence.	Foundational (L 15)
Normal dispersion	A condition in wave propagation where the phase velocity ($u_p$) decreases as the angular frequency ($\omega$) increases, leading to $u_g<u_p$.	Foundational (L 14)
Anomalous dispersion	A condition where the phase velocity ($u_p$) increases as the angular frequency ($\omega$) increases, leading to $u_g>u_p$.	Foundational (L 14)

6. Radio Wave Propagation

Term	Definition	Year of Appearance
Plasmas	Ionized gases (such as those in the ionosphere) where the free electron and positive ion densities are essentially equal.	Foundational (L 14)
Line of sight (LOS) communication	A propagation mode where radio waves travel in a direct, straight path from the transmitting antenna to the receiving antenna without relying on reflection.	2019, 2016