Practice question

**Transverse nature** means E and B perpendicular to direction, e.g., wave propagating along z, E along x, B along y, Poynting vector S = E×B/μ₀ along z, energy flow direction. E and B in phase, maxima together, ratio fixed c. Electromagnetic waves require no medium for propagation, as they are self-sustaining oscillations of electric and magnetic fields, allowing them to travel through the vacuum of interstellar space. Using c = fλ, E₀/B₀ = c, I_d = ε₀ dΦ_E/dt, and spectrum classification λ = c/f, evaluation yields No medium required, illustrating EM wave transverse nature and Maxwell's displacement current concept.