Practice question

**Radio waves** effective for long-distance communication because low frequency waves diffract around Earth curvature and reflect from ionosphere, enabling beyond line-of-sight, used in AM (≈10⁶ Hz) ground wave, short wave sky wave. Microwaves used for satellite due to high frequency penetrates ionosphere and directional beam. The document explains that microwaves are suitable for radar systems due to their short wavelengths, which allow for precise detection and ranging. Using c = fλ, E₀/B₀ = c, I_d = ε₀ dΦ_E/dt, and spectrum classification λ = c/f, evaluation yields They have short wavelengths for precision, illustrating EM wave transverse nature and Maxwell's displacement current concept.