NE 241: Electromagnetism

Sources and References

Equivalent UW courses — PHYS 242 (Electricity and Magnetism 1), PHYS 342 (Electricity and Magnetism 2), PHYS 122 (Waves, Electricity and Magnetism) Primary textbook — Knight, R. D. Physics for Scientists and Engineers: A Strategic Approach (Volume 4), Pearson Addison-Wesley (2nd/3rd edition). Supplementary references — Griffiths, Introduction to Electrodynamics (used in PHYS 342 for comparison)

Equivalent UW Courses

NE 241 is the Nanotechnology Engineering sequence’s single-term treatment of classical electromagnetism. Its calendar content — Coulomb’s law through Maxwell’s equations and plane waves — spans what the Physics department splits across PHYS 122 (intro-level E&M for engineers and physical-science majors) and PHYS 242 (the sophomore honours course on electrostatics, magnetostatics, and induction). The wave and Maxwell-equation material at the end of NE 241 overlaps the opening chapters of PHYS 342, where the full differential form of Maxwell’s equations and electromagnetic wave propagation are developed more rigorously. Roughly, NE 241 ≈ PHYS 122 + core of PHYS 242 + introductory portion of PHYS 342, compressed to one term.

What This Course Adds Beyond the Equivalents

NE 241 emphasizes the engineering side: capacitors and inductors as circuit elements, dielectric/magnetic materials in device contexts, and polarization with an eye toward nanoscale and photonic applications. The lab component introduces hands-on measurement of fields, fluxes, and EM phenomena, which PHYS 242 does not always include. Knight’s textbook takes a concept-first integral-form approach (flux tubes, field lines, energy arguments) rather than the tensor-and-vector-calculus style of Griffiths.

What NE 241 omits relative to PHYS 242/342: less emphasis on boundary-value problems (separation of variables, Legendre polynomials, image charges), no multipole expansion, and minimal treatment of retarded potentials, gauge choices, or radiation from accelerated charges. Students who want the rigorous Green’s-function / vector-calculus treatment need PHYS 342 or a later electrodynamics course.

Topic Summary

Electrostatics — Coulomb, Field, Flux

Coulomb’s law for discrete and continuous charge distributions; superposition; the electric field \( \vec{E} \) as force per unit test charge. Electric flux and Gauss’s law in integral form, applied to spherical, cylindrical, and planar symmetries. Covered in Knight chapters on charges and fields.

Electric Potential and Energy

Scalar potential \( V \), the relation

\[ \vec{E} = -\nabla V, \]

potential of point charges and continuous distributions, and electrostatic potential energy. Conductors in equilibrium, equipotential surfaces, and capacitance — including parallel-plate, cylindrical, and spherical geometries with and without dielectrics.

Currents, Resistance, and DC Circuits

Current density, Ohm’s law in local form \( \vec{J} = \sigma \vec{E} \), resistance, and power dissipation. Kirchhoff’s laws, RC transients. Treated more briefly than in a full circuits course since ECE 140 handles circuit analysis elsewhere.

Magnetostatics

Magnetic field from moving charges and currents, Biot–Savart law, and Ampère’s law for solenoids, toroids, and infinite wires. Force on currents and the Lorentz force \( \vec{F} = q(\vec{E} + \vec{v} \times \vec{B}) \). Magnetic dipoles and materials (para-, dia-, ferromagnetism) at a descriptive level.

Electromagnetic Induction

Magnetic flux, Faraday’s law, Lenz’s law, and motional EMF. Self- and mutual inductance; energy stored in magnetic fields. RL and LC transients and the physical origin of induced electric fields.

Maxwell’s Equations and Waves

Displacement current and the full set of Maxwell’s equations in integral form. Derivation of the wave equation for \( \vec{E} \) and \( \vec{B} \) in vacuum, plane-wave solutions, the speed of light \( c = 1/\sqrt{\mu_0 \varepsilon_0} \), energy flow via the Poynting vector, and linear polarization. Brief discussion of reflection and the EM spectrum.

Laboratory Component

Experiments on electrostatic fields, RC/RL circuits, magnetic field mapping, Faraday induction, and oscilloscope-based measurements of EM waveforms. The lab emphasizes instrumentation and uncertainty rather than theoretical derivation.