EM Waves ↔ Electrostatics (Chapters: Electric Charges, Gauss's Law)

• Gauss's law for electricity (∮E·dA = q_enc/ε_{0}) is Maxwell's first equation
• Same ε_{0} = $8.85 \times 10^{-12}$ $C^{2}$/(N·$m^{2}$) appears in both displacement current and capacitor formulas
• Capacitor charging → displacement current → this chapter

EM Waves ↔ Magnetism (Chapters: Magnetic Effects of Current)

• Ampere's law is modified by adding displacement current (this chapter)
• Original ∮B·dl = μ_{0}I_c → Modified ∮B·dl = μ_{0}(I_c + ε_{0}dΦ_E/dt)
• Same μ_{0} = 4π×10^{-7} H/m appears in both Biot-Savart and c = 1/√(μ_{0}ε_{0})

EM Waves ↔ Electromagnetic Induction

• Faraday's law (∮E·dl = –dΦ_B/dt) is Maxwell's third equation
• Mutual regeneration of E and B in EM wave is the same coupling as in EM induction
• Transformers and generators use the same Faraday law that Maxwell used in wave equations

EM Waves ↔ Optics (Chapters: Ray Optics, Wave Optics)

• Visible light is an EM wave (λ = 400–700 nm)
• Reflection, refraction, interference, diffraction — all applicable to EM waves
• Refractive index n = c/v arises because EM waves slow down in media (n > 1)
• Dispersion (different speeds in medium) = different refractive indices for different λ

EM Waves ↔ Modern Physics (Chapters: Atoms, Nuclei, Photoelectric Effect)

• Photoelectric effect: light has photon nature; E = hf (photon energy)
• X-rays produced in atoms (inner-shell electron transitions); gamma rays from nuclei
• Radiation from nuclear decay → gamma rays → this chapter

EM Waves ↔ Communication Systems

• Radio waves, microwaves used for communication
• EM spectrum knowledge directly applied in communication chapter
• Frequency allocation: AM radio (kHz), FM radio (MHz), TV (VHF/UHF), mobile (GHz)