Practice question

**Visible light** λ≈400-700 nm, f≈4×10¹⁴ to 7×10¹⁴ Hz, narrow part of spectrum sensitive to human eye, produced by atomic transitions, used for vision, photosynthesis, optical fibers, central frequency ≈5×10¹⁴ Hz, different colors correspond to different λ. Visible light corresponds to the peak wavelength distribution of solar radiation, making it the most abundant light on Earth, to which human eyes adapted for survival. Using c = fλ, E₀/B₀ = c, I_d = ε₀ dΦ_E/dt, and spectrum classification λ = c/f, evaluation yields Its abundance in solar radiation, illustrating EM wave transverse nature and Maxwell's displacement current concept.