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#antennas

2 public questions tagged with this topic.

Applications of EM Waves in Communication and Medicine

Why are microwaves used in satellite communication?

**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. Microwaves can penetrate the atmosphere with minimal absorption and are easily directed into narrow beams, making them ideal for satellite communication over long distances. Using c = fλ, E₀/B₀ = c, I_d = ε₀ dΦ_E/dt, and spectrum classification λ = c/f, evaluation yields Penetration and directionality, illustrating EM wave t

Ref: NCERT > Physics Book > Electromagnetic Waves > Applications of EM Waves in Communication and Medicine

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Electromagnetic Spectrum - Radio Waves and Microwaves

Which type of electromagnetic waves are produced by the rapid acceleration and deceleration of electrons in aerials?

**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 states that radio waves are produced by the rapid acceleration and deceleration of electrons in aerials. Using c = fλ, E₀/B₀ = c, I_d = ε₀ dΦ_E/dt, and spectrum classification λ = c/f, evaluation yields Radio waves, illustrating EM wave transverse nature and Maxwell's displacement current

Ref: NCERT > Physics Book > Electromagnetic Waves > Electromagnetic Spectrum - Radio Waves and Microwaves

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