Why are microwaves used in speed guns to time fast-moving objects?
**Microwaves** λ≈10⁻³ to 0.3 m, f≈10⁹ to 10¹² Hz, produced by klystron/magnetron, used in microwave ovens because frequency ≈2.45 GHz matches rotational resonance of water molecules, causing dielectric heating, also radar, satellite communication due to small wavelength allows directional beams. The document mentions that microwaves are used in radar systems (like speed guns) due to their short wavelengths, which allow precise measurements. 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 E
Ref: NCERT > Physics Book > Electromagnetic Waves > Electromagnetic Spectrum - Radio Waves and Microwaves
