Practice question

**Ultraviolet** λ≈10-400 nm, produced by atomic transitions and Sun, causes fluorescence, sterilization, harmful to eyes/skin, absorbed by ozone layer. **X-rays** λ≈10⁻² to 10 nm, produced by rapid deceleration of energetic electrons in X-ray tube, used in medicine for diagnosis (shadow of bones) and cancer therapy due to high ionization and penetration, detected by photographic film and Geiger counter. The document states that ultraviolet rays range from about 400 nm to 0.6 nm . Using c = fλ, E₀/B₀ = c, I_d = ε₀ dΦ_E/dt, and spectrum classification λ = c/f, evaluation yields 400 nm to 0.6 nm, illustrating EM wave transverse nature and Maxwell's displacement current concept.