Practice question

**Microwaves in ovens** cause water molecules to rotate at 2.45 GHz, friction heats food, penetration depth few cm, efficient heating, also radar uses reflection of microwaves from objects, Doppler shift measures speed, medical diathermy uses microwaves for tissue heating. As per the document, X-rays have wavelengths from about 10⁻⁸ m (10 nm) to 10⁻¹³ m ( 10⁻⁴ nm ). Using c = fλ, E₀/B₀ = c, I_d = ε₀ dΦ_E/dt, and spectrum classification λ = c/f, evaluation yields 10 nm to 10⁻⁴ nm, illustrating EM wave transverse nature and Maxwell's displacement current concept.